Drag and drop images here, or choose files. Processing stays in your browser—nothing is uploaded to SynthQuery servers.
Up to 36 files · max 48 MB each · GIFs export first frame only
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Used for JPEG/WebP when padding appears (contain mode or transparency).
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About this tool
SynthQuery’s Image Resizer is a free, browser-based utility for changing the pixel dimensions of photographs, illustrations, screenshots, and marketing assets without installing desktop software. You can target a specific width or height while preserving aspect ratio, scale the longest or shortest edge to a maximum you choose, resize by percentage for quick batch harmonization, or lock output to an exact canvas using contain (letterbox), cover (center crop), or stretch modes. Rotation in ninety-degree steps, horizontal and vertical flips, and export to WebP, JPEG, or PNG—with an adjustable quality slider for lossy formats—make it practical for social templates, Open Graph cards, hero images, email graphics, and documentation figures. Everything runs locally in your tab: files are decoded with standard browser APIs, drawn to an off-screen canvas, and downloaded again as new rasters, which means SynthQuery does not receive your image bytes for resizing. The tool belongs to our Free tools series alongside the WebP Converter, HTML Online Viewer, pixel converters, Word Counter, Dictionary, and Grammar Checker, while the full catalog at /tools adds AI detection, readability scoring, plagiarism checks, and rewriting when your pipeline moves from pixels to prose.
What this tool does
Raster resizing is fundamentally a sampling problem: the tool reads your source bitmap, maps each output pixel to a neighborhood of input pixels, and writes a new grid. Browsers apply high-quality interpolation when drawing into a canvas at non-integer scales, which is why downsizing a twelve-megapixel photo to a twelve-hundred-pixel hero typically looks crisp, while aggressive upscaling cannot invent real detail—it smooths and guesses, so you should prefer exporting larger masters from a camera or design file whenever possible. SynthQuery exposes the control surface product teams actually argue about in reviews: whether marketing wants every carousel tile to share one height, whether developers need WebP for LCP budgets, whether legal insists JPEG for certain archival emails, or whether designers need PNG when alpha channels must survive a round trip through a CMS.
The dimension modes map to those debates directly. Width-only and height-only modes preserve aspect ratio by scaling uniformly from the effective dimensions after rotation, which is how you keep portrait and landscape shots visually consistent inside a component library without manually calculating companion heights. Longest-edge and shortest-edge caps are ideal when you enforce a maximum bounding box—think “nothing wider than sixteen hundred CSS pixels” or “icons must be at least sixty-four on the short side”—without caring which axis was dominant in the original capture. Percentage mode supports relative batch operations, such as producing a fifty-percent preview set for stakeholders or generating derivative thumbnails that remain proportional when source resolutions differ. Exact canvas mode is where layout precision meets photography: contain fits the entire image inside your chosen rectangle and fills leftover space with a letterbox color you pick, which mirrors how many design tools export “safe” regions for variable aspect devices; cover fills the rectangle and may crop excess, similar to background-size: cover in CSS; stretch ignores aspect ratio and maps the image to every pixel of the canvas, useful only when distortion is acceptable or when correcting non-square source quirks you plan to replace later.
Output format choice interacts with transparency and compression. PNG is lossless for typical screenshots and UI chrome with sharp edges; file sizes can grow quickly on photographs. JPEG discards high-frequency detail to save bytes and does not preserve alpha; any transparent regions become the letterbox color you select. WebP balances modern compression with optional transparency in supporting browsers and is a common default for web performance checklists. Quality sliders for JPEG and WebP trade visual fidelity against byte weight: mid-to-high values often look indistinguishable from lossless in social-sized outputs while shrinking payloads for Core Web Vitals. EXIF metadata, ICC color profiles, and GPS tags are not carried through canvas export by design—you receive a clean raster, which is usually desirable before publishing but means you should archive originals elsewhere if provenance matters.
Animated GIFs decode to their first frame in this pipeline, which the interface states explicitly so motion designers are not surprised. SVG inputs may work when the browser rasterizes them, but complex SVG features or external references can fail to decode; for vector-first workflows, keep Illustrator, Figma, or Inkscape in the loop. Batch download walks the queue sequentially with short delays so browsers allow multiple save prompts without silently blocking them, and each filename appends “-resized” before the extension for clear versioning beside your masters.
Use cases
Growth marketers resize hero and blog imagery to the exact Open Graph and Twitter card dimensions their CMS validators expect, then export WebP for production and JPEG fallback where legacy pipelines require it. E-commerce operators normalize supplier JPEGs that arrive at inconsistent megapixel counts so category grids load uniformly and Largest Contentful Paint stays predictable on mobile networks. Support teams crop and downscale screenshots before attaching them to tickets, redacting sensitive chrome first in an editor if needed, then using contain mode with a neutral pad color that matches the company dark theme.
Developers preparing responsive srcset candidates generate several width steps from one master without opening Photoshop, then pair the results with our PX to CM or PX to Inches utilities when print collateral must match a landing page. Content designers working in Notion-like workflows batch fifty assets after a photoshoot, longest-edge capped at two thousand pixels, before uploading to a DAM that bills on storage. Email coders remember that many clients ignore WebP reliably unless a fallback exists; they still use the resizer to enforce maximum widths and to rotate accidental portrait product shots exported from phones.
Educators and students learn the relationship between pixel dimensions, file size, and perceived sharpness when projectors display the same image at different scales. Journalists in the field compress images on a locked-down laptop before filing over satellite links, accepting that metadata stripping is part of the export. Accessibility advocates pair correctly sized imagery with alt text checked in the Grammar tool and reading level reviewed in SynthRead so the words around images remain understandable. Localization teams duplicate queues per locale when only the banner text overlay differs but the photo crop should stay identical—exact cover mode at a fixed canvas enforces that discipline.
Researchers preparing figures for submissions resize to journal line-art guidelines, then move to desktop vector tools if editors demand EPS. Game modders flip and rotate texture extracts quickly before re-importing into engines. Even personal users shrinking vacation albums for grandparents’ tablets benefit from percentage mode and honest file naming.
How SynthQuery compares
Consumer resizers range from single-field toys that silently upload to opaque servers, to heavyweight editors with layers you do not need for a straightforward scale-and-save. SynthQuery targets professionals and students who want explicit geometry modes, accountable privacy, and adjacency to the rest of the SynthQuery writing and verification stack. The matrix below summarizes common differences; pick tools based on whether you need server-side storage, collaborative layers, or a fast, explainable local pass.
Aspect
SynthQuery
Typical alternatives
Privacy model
Decode, draw, and encode in your browser; no image upload to SynthQuery for the resize operation.
Many free sites upload files to cloud workers for conversion and analytics.
Geometry controls
Width, height, longest/shortest edge, percent, exact canvas with contain, cover, or stretch.
Often one box for width or a blind percentage without crop semantics.
Separate tools for rotation versus compression; limited WebP or batch.
Workflow context
Linked from /free-tools and /tools near WebP Converter, converters, HTML viewer, grammar, and AI tools.
Standalone pages disconnected from copy quality and detection workflows.
Honest limits
GIF animation exports first frame only; heavy upscaling cannot recover real detail; canvas size caps for stability.
Some products imply AI upscaling quality without clarifying training data or rights.
How to use this tool effectively
Start from the highest-quality master you are allowed to use—RAW or high-bit-depth exports beat already-compressed social downloads when you need a new derivative. Drag files into the queue or browse; watch for GIF warnings if you expected motion. Select the item you want to preview; the panel shows original pixel dimensions and the output canvas after your settings apply.
Choose a resize mode that matches your stakeholder request. If the brief says “max width twelve hundred,” use width mode. If the channel spec lists a fixed rectangle such as twelve hundred by six hundred for ads, switch to exact canvas: try contain when no crop is acceptable, cover when the frame must be filled, stretch only when art direction approves distortion. Set longest-edge mode when you normalize a mixed bag of portrait and landscape shots to a shared bounding box. Use percentage when someone asks for “half-size placeholders” across heterogeneous sources.
Apply rotation and flips before judging crops—orientation changes which edge is longest. Pick WebP when the destination stack supports it and you want smaller bytes; choose PNG for sharp UI captures; choose JPEG for photographic smooth gradients where transparency is irrelevant. Adjust quality until file size and visual noise meet your performance budget; if letterboxing appears, set the pad color to match your page background so the transition is invisible.
Download the selected image to validate in context, then use Download all when the queue is ready. Rename externally if your DAM requires strict conventions; SynthQuery appends “-resized” automatically. When the surrounding article or landing copy still needs polish, open the Grammar Checker and SynthRead; if AI-generated captions accompany the image, run the AI Detector per policy. Bookmark /tools for the full catalog and /free-tools for utilities.
Limitations and best practices
Canvas resizing does not replace dedicated color management for print: embedded ICC profiles from your camera may be lost on export, so prepress still belongs in tools that preserve or convert profiles explicitly. CMYK separations, spot colors, and layered PSD smart objects are out of scope—flatten in your design package first. Upscaled images cannot recover true optical resolution; marketing claims about “enhancing” tiny assets should be treated skeptically. Very large dimensions are clamped to protect browser stability; split enormous panoramas in specialist software if you routinely exceed those bounds. Accessibility requires more than pixel size: provide meaningful alt text, avoid text inside images when live HTML can carry it, and test contrast for overlays. For EXIF-sensitive journalism or HR contexts, confirm whether stripping metadata is legally and ethically appropriate before publishing derivatives. Always keep an untouched original when contracts or forensic review might require it.
Review AI-assisted captions or landing copy where disclosure policies apply.
Frequently asked questions
No. After you pick files, the browser decodes them locally, draws the resized result to an in-memory canvas, and encodes a new file for download. That matches how many privacy-conscious teams expect lightweight utilities to behave on locked-down laptops. Network activity you might still see comes from loading the SynthQuery web application itself, analytics if enabled by your deployment, or any remote fonts—not from shipping your image bytes to us for processing. If you need an air-gapped guarantee, use the tool offline once the page is cached or self-host a static mirror per your security policy. Corporate proxies that inspect HTTPS can still see domain connections, so classify the workflow according to your data-handling standard. In short, the resize math stays on your device.
Choose WebP when your site or app stack serves modern formats and you want smaller files at comparable visual quality; it is widely supported in evergreen browsers and aligns with performance guidance about next-gen images. Choose JPEG for photographs when transparency is unnecessary and when downstream systems reject WebP—email clients and some legacy CMS attachments still favor JPEG. Choose PNG when you need crisp edges, flat UI screenshots, or partial transparency; file sizes rise on photo-like content, so prefer WebP or JPEG for large continuous-tone images when alpha is not required. You can export the same queue item multiple times with different settings to compare byte weight visually. Always validate in the environment where assets will render, not only on your development monitor.
Contain scales the image uniformly until the entire picture fits inside your target rectangle, adding empty space (letterboxing) if aspect ratios differ—ideal when losing any edge content is unacceptable. Cover also scales uniformly but fills the entire rectangle, cropping whatever does not fit, similar to CSS background-size cover; use it when the frame must be full-bleed and you can center on the important subject. Stretch maps width and height independently, which distorts proportions and should be reserved for rare fixes or placeholder art. Letterbox color matters for contain when exporting JPEG or WebP without transparency; pick a color that matches your page background. For strict brand crops, storyboard the safe zone before relying on automated center crops.
No. Canvas-based export produces a new raster without embedded EXIF, GPS, lens, or copyright blocks. That is often desirable before publishing consumer photos to the public web because it reduces accidental location leaks and file size. If you must retain metadata for archival, legal, or forensic reasons, keep the original files in a DAM and store derivatives separately with clear naming. Orientation from EXIF is typically honored when the browser decodes the source, so rotated phone shots usually appear upright before you add extra rotation; if something looks sideways, use the ninety-degree rotation controls deliberately. For color-critical workflows, remember ICC profiles may also be dropped—reconcile with desktop software when print contracts demand it.
The HTML canvas pipeline used here rasterizes a single frame; it does not rebuild multi-frame GIF timing tables. That limitation keeps the implementation predictable across browsers and avoids silently corrupting animations. If you need resized GIFs or MP4 fallbacks, use video or motion tools that understand timelines. For short UI demos, consider screen recordings instead of gigantic GIFs, which are notoriously inefficient on bandwidth. When only the first frame matters—such as a thumbnail preview of a meme—this behavior may be acceptable; otherwise convert formats upstream. Document the behavior in your team playbook so designers do not assume animated exports.
Practical limits combine browser memory, canvas maximum dimensions, and fair-use caps shown in the interface. Extremely wide panoramas or deep megapixel stacks may fail to decode on low-RAM mobile tabs even when desktop succeeds. Output dimensions are clamped to a safe maximum to prevent freezing; if you routinely exceed that, preprocess in desktop editors. File count queues are capped so tabs remain responsive; run multiple passes if you have hundreds of assets. Upsizing beyond the native resolution spreads each source pixel across many outputs—expect softness. For production hero images, prefer sourcing at or above the display size you need, then downscale here. Monitor DevTools memory if you batch very large TIFF conversions that the browser even accepts.
You can match pixel counts that correspond to physical inches at three hundred DPI—for example, three thousand pixels across maps to ten inches—but this tool does not embed DPI metadata tags or manage CMYK separations. Print vendors often ask for PDF/X or TIFF with explicit color profiles; deliver those from InDesign, Affinity, or Photoshop when contracts require. Use SynthQuery’s PX to CM or PX to Inches utilities alongside this resizer to reason about centimeters and inches from pixel widths, then finalize in a color-managed chain. For office printing on laser devices, RGB JPEGs at correct pixel dimensions are frequently sufficient, but always confirm bleed, safe margins, and black generation rules with the print shop.
Browsers may throttle multiple programmatic downloads initiated in quick succession as a pop-up or abuse mitigation measure. SynthQuery spaces downloads slightly and names each file distinctly so you can allow multiple saves when prompted. If your browser blocks batch saves, download individually or adjust site permissions. Safari and mobile WebKit sometimes behave more conservatively than desktop Chrome; plan manual verification on iOS if that is a primary audience. Enterprise policies can disable automatic downloads entirely—consult IT if nothing appears. For DAM ingestion, consider zipping locally with your own scripts after downloading each derivative, since this page does not produce a single archive file.
Correct dimensions and byte weight indirectly support SEO and user experience signals: smaller, appropriately sized images reduce transfer time and help Largest Contentful Paint, while oversized originals waste crawl budget on CDNs and frustrate mobile users. Google’s guidance consistently recommends serving responsive images with modern formats and compression; this tool helps you produce those derivatives quickly. SEO also depends on alt text, context, structured data, and page copy—pair image work with the Grammar Checker and meaningful headings. Do not substitute tiny illegible text graphics for live HTML text; search engines and screen readers both suffer. Measure with Lighthouse or field data after deployment rather than assuming any single export setting is perfect forever.
Visit /free-tools for the full Free tools hub—search, filter by pillar, and open utilities such as the WebP Converter, HTML Online Viewer, markup and PPC calculators, pixel converters, Word Counter, Dictionary, and Grammar Checker. The broader catalog lives at https://synthquery.com/tools, linking AI detection, SynthRead readability, plagiarism scanning, humanizer, paraphraser, summarizer, and other paid-tier features when your workflow grows beyond quick utilities. Bookmark both pages: /free-tools for daily scratch work, /tools when you need the complete product map. Footer navigation on synthquery.com also points to these hubs for consistent discovery.