A top-bottom collage—sometimes called a vertical stack, vertical photo strip, or “TikTok-style” story board—is one raster image made by placing two to five pictures in a single column, top to first upload order and bottom to last. Unlike a carousel of separate files or a PDF with multiple pages, the result is one continuous pixel canvas you can drop into a blog, LMS module, email body, or social scheduler as a single attachment. That matters when platforms expect one hero asset, when you want guaranteed reading order without swipe UI, or when you are comparing versions of a product, UI screen, or data viz in one tall frame.
SynthQuery’s Top-Bottom Collage tool (COLL-004) runs entirely in your browser. You upload JPG, PNG, WebP, BMP, or TIFF sources, reorder them with accessible move controls, pick a target output width so every row shares the same column width (aspect ratios are preserved—tall photos stay tall, wide photos shrink in height), and set a gap measured in pixels filled with a color you choose. The live preview updates on Canvas so what you see is what you encode. Export to PNG for lossless edges, JPEG for smaller long-form posts, or WebP when your channel accepts it. Nothing is sent to SynthQuery for compositing; decoding and drawing use the same HTML5 Canvas primitives documented across our other imaging utilities.
Why vertical stacking instead of side-by-side
Horizontal collages excel at before/after pairs and dual screenshots. Vertical stacks shine when the story reads downward: recipe steps, release notes with screenshots, training checkpoints, or “version 1 → version 2 → shipped” narratives. A single tall JPEG survives email clients that flatten carousels, attaches cleanly to support tickets, and pins well on boards that favor height. When you later need motion, you can still feed the same ordered frames into GIF from Photos for a lightweight animation.
Who uses this workflow
Marketers building Pinterest-ready tall pins often normalize width first so typography overlays line up. Educators stack lab photos or whiteboard captures for one downloadable summary. Developers paste sequential UI states for changelog posts. E-commerce teams combine pack shots with detail macros without opening a desktop suite on a locked-down laptop. Because processing stays local, agencies can run it in client VMs that forbid cloud pixel upload.
What this tool does
Vertical stacking is deterministic: for each source, SynthQuery computes a draw height proportional to the chosen column width, then sums heights plus gaps. That is simpler than smart panoramas that warp pixels to align features, and more predictable for infographic work where you want explicit control. The gap color doubles as a design element—white for clean editorial, black for OLED-friendly posts, brand hex for bordered social stories.
Auto-matched widths mean you never manually resize five assets in a separate batch step before stacking. Presets accelerate compliance with common pixel widths while “Match widest image” preserves the native resolution of your largest horizontal dimension, helpful when every source already shares a camera output size. The preview canvas mirrors the export path so you are not surprised by JPEG chroma subsampling after the fact—you toggle formats and watch the preview refresh.
Mobile layout stacks controls vertically with large touch targets; preview scrolls horizontally if the collage is wider than the viewport so landscape photos remain inspectable. Keyboard-accessible move/remove actions pair with aria-label attributes on icon buttons for screen reader clarity. Download state shows a spinner to prevent double taps on slower phones encoding megapixel strips.
Gap as design-negative space
Small gaps read as subtle separation; large gaps mimic mat boards. Because the color is uniform, you can simulate thin rules by keeping gap at two to four pixels with a high-contrast tone against both photographs.
Format trade-offs on tall canvases
JPEG excels when photos dominate and file size caps matter—think email attachments. PNG preserves text overlays and UI chrome. WebP often splits the difference but verify your CMS or messaging client actually serves it without server-side conversion surprises.
Performance and limits
Browsers impose practical canvas area ceilings; SynthQuery guards extremely tall outputs that could freeze tabs. If you approach the limit, prefer matching width to the smallest acceptable template rather than full-resolution DSLR stacks.
Technical details
Composition uses a temporary HTML canvas element sized to the computed layout width and total height. The engine fills the canvas with the user-selected gap color, then calls drawImage for each scaled rectangle at integer-rounded positions derived from floating-point layout math. Width normalization divides each source’s natural height by its natural width, multiplies by the target column width, and rounds to the nearest pixel for row height—standard proportional scaling without cropping.
Images decode through the browser’s built-in pipeline; EXIF orientation is respected to the extent the underlying Image element applies it. Transparency in PNG or WebP sources composites over the gap color rather than leaving checkerboard holes unless you export PNG with alpha preserved in regions outside drawn rectangles—note that the full canvas background remains opaque once filled. TIFF and BMP support depends on browser capabilities; if decode fails, the UI surfaces an error.
No WebAssembly or server round trip is required for COLL-004. File size limits protect mobile GPUs from accidental hundred-megapixel bursts. The implementation aligns with other SynthQuery Canvas utilities: deterministic math in a small pure function for layout, imperative draw for preview and download, and MIME-specific encoding via canvas.toBlob with quality parameters for lossy formats.
Why integer rounding on heights
Sub-pixel row heights would leave fractional gaps when summed; rounding per row keeps the canvas height an exact sum of integer draw heights plus integer gap bands, preventing off-by-one drift in strict pixel environments.
Color picker versus CSS variables
Gap color uses the native color input’s sRGB hex string for canvas fillStyle compatibility across engines. It is independent of site theme tokens so exported pixels match what you picked, even when the app shell uses OKLCH styling.
Use cases
Pinterest and vertical social feeds reward height: recipe bloggers stack ingredient photo, mise en place, and plated result; SaaS marketers stack hero, feature callout, and testimonial stills for a single pin export. Infographic-style explainers place chart, caption crop, and citation screenshot in one column for embedding in Notion or Confluence where multi-image galleries are cumbersome.
Progress tracking for fitness, renovations, or growth experiments often wants a dated vertical strip for sharing in community threads—upload week one through week three, keep width consistent, and the story reads top to bottom. Tutorial steps for software or hardware pair naturally with vertical stacks when each step is a screenshot; gap color can separate conceptual phases without extra design software.
Social media stories and temporary highlights sometimes need one asset that already includes the sequence, avoiding platform carousel compression differences between slides. Internal QA teams attach one tall PNG to Jira tickets showing reproduction steps. Educators bundle microscope or field samples for a single download link in the syllabus.
Comparative storytelling
When the narrative is “before, during, after,” vertical order encodes time. Pair with concise captions outside the image for accessibility; the collage carries visual continuity while text carries semantics.
Brand-safe handoffs
Agencies can produce one approved strip per deliverable so clients do not rearrange frames in a carousel. Locked order reduces approval cycles when legal must sign off on each visual in sequence.
How SynthQuery compares
Desktop suites like Photoshop or Affinity offer artboards, smart guides, and non-destructive layers—ideal when you are building complex composites hourly. SynthQuery targets the lightweight moment: you already have finals, you just need a trustworthy vertical strip without licensing a pixel editor on a guest machine. Compared with cloud collage sites that upload your bytes to a GPU farm, this page keeps bitmaps in-tab. Compared with stitching panoramas, it avoids projection math—you explicitly choose order and spacing. Compared with PDF merge tools, it outputs one raster suited to image-first channels rather than paginated documents.
Aspect
SynthQuery
Typical alternatives
Data residency
Decode and draw occur in the browser session; collage bytes are not sent to SynthQuery for stacking.
Some online collagers upload to servers for GPU compositing unless explicitly offline-first.
Layout model
Explicit vertical list with fixed column width, proportional heights, solid-color gaps.
Template grids or AI auto-layout may crop unpredictably.
Output type
Single PNG, JPEG, or WebP raster download.
PDF merges or multi-slide decks require different viewers.
Learning curve
Reorder list, three sliders/selects, download.
Layer-based editors expose hundreds of commands for unrelated tasks.
How to use this tool effectively
Open Top-Bottom Collage on SynthQuery and click Upload images. Select between two and five files in the order you roughly want; you can refine order afterward. The tool accepts common eight-bit raster types browsers decode reliably—JPG, PNG, WebP, BMP, and TIFF—with a per-file size guard so mobile tabs do not exhaust memory. If a file fails decode, you will see a toast instead of a silent blank preview.
Each row shows a thumbnail, filename, native pixel dimensions, and buttons to move the clip up or down in the stack. The top row becomes the uppermost region of the exported collage. Remove mistakes with the trash control; add more images until you reach the maximum of five or your creative minimum of two. When fewer than two images remain, download stays disabled because a collage, by definition, merges multiple sources.
Choose Gap between images in pixels. Zero gap yields pixel-perfect contact—useful for seamless screenshots—while larger values create breathing room or faux matting. Set Gap / border color with the color picker or by typing a hex value; that color fills every band between images and any conceptual “canvas background” behind them before rows are painted, so transparent PNGs still composite over the chosen matte.
Under Output width, pick Match widest image to keep the full resolution of your broadest source, or select a preset such as 720, 1080, 1200, or 1920 pixels to align with social templates. Custom width accepts values between 16 and 8192 for specialized deliverables. Width matching scales every image to the target width independently; heights adjust proportionally, which is the standard “same column width” behavior designers expect from vertical stacks.
Select Export format: PNG preserves sharp UI edges and alpha-friendly workflows; JPEG and WebP offer quality sliders for smaller byte sizes on long canvases. Watch the live Preview canvas for the exact aspect; it reflects gap, color, width, and order. When satisfied, press Download collage to save a single file named from your first image with a suffix. Bookmark /free-tools to rediscover the utility alongside calculators, converters, and content QA products.
Step 1: Curate and order frames
Start from masters that are already rotated the way you intend to publish; the stack respects decoded bitmap orientation. If EXIF rotation matters, confirm in a viewer first—Canvas uses browser decode semantics. Prefer sRGB exports when color-critical; the tool does not embed ICC profiles beyond what the encoder provides.
Step 2: Tune spacing and width
Match your destination: Pinterest long pins often land near 1000 px wide; blog content may prefer 1200 px; quick Slack proofs may need only 720 px. Wider targets increase total pixel count—if the UI warns about limits, reduce width, shrink gap, or drop a frame.
Step 3: Export and distribute
PNG is safest for UI with sharp lines; JPEG smooths photographs but recompresses; WebP balances size when platforms accept it. After download, run your usual accessibility checks—add alt text describing the composite story, not just “image123.”
Limitations and best practices
This is not a panorama stitcher: it does not align overlapping edges, remove ghosts, or blend exposures. It is not a PDF composer: use PNG/JPEG to PDF merge utilities when you need selectable pages. Animated sources decode to still frames in many browsers—export GIF or video frames first with our GIF frame extractor or video frame extractor if motion must remain motion.
Very tall exports can challenge email attachment limits and in-app image viewers; consider width presets or split narratives when byte size explodes. Always respect copyright and model releases for every stacked photo. For text-heavy composites, verify contrast of any captions you burn in elsewhere before publishing. After visual work, if accompanying copy uses AI assistance, review SynthQuery’s detector and humanizer policies for disclosure expectations.
Normalize individual assets before stacking when upstream sources mix wildly different megapixel counts.
Frequently asked questions
You can combine between two and five images per export. Two is the minimum to qualify as a collage; five caps memory use on phones and keeps the interface simple. If you need more frames, run multiple passes—export a first strip, then treat it as a single source in another tool—or switch to GIF from Photos for longer sequences, or PNG to PDF merge when pagination is acceptable.
No. Each image scales to the chosen output width while preserving aspect ratio. Nothing is center-cropped unless you pre-cropped elsewhere. Taller aspect ratios produce taller rows; wider sources shrink vertically after width normalization. If you need hard crops to identical heights, use a crop preset tool first, then return to stack.
The gap color paints the canvas before images are drawn, so the space between stacked rows shows that color. It also appears anywhere a transparent PNG does not cover pixels—think partial alpha fades—because the background is a solid matte. Pick white for a clean editorial gutter, black for OLED-friendly separation, or a brand hex to echo template frames.
Compositing uses local Canvas operations in your browser tab. Ordinary site assets or analytics may still load as you browse, but your photographs are not transmitted to SynthQuery for stacking. For strict air-gapped policies, follow your IT guidance on offline browser profiles; the architecture matches other client-side SynthQuery imaging utilities.
PNG is lossless and ideal for UI screenshots, text, and logos. JPEG reduces file size for photo-heavy stacks but recompresses and can introduce artifacts on sharp edges—tune the quality slider before download. WebP often balances size and quality when destinations support it; verify CMS and email clients because some still transcode uploads. None of the formats carry separate layers; the download is a flattened raster.
A collage merges multiple visuals into one narrative column. With one image, you already have a single asset—use Image Resizer or format converters instead. The UI enforces two images minimum to prevent accidental redundant exports and to keep instructional copy aligned with the feature name.
Yes. Controls stack vertically, touch targets follow shadcn sizing, and previews scroll when the collage is wider than the viewport. Very large pixel dimensions may stress older phones; if encoding feels slow, reduce target width or gap. Safari and Chrome on iOS both support the Canvas APIs used here, though extreme TIFFs may decode slower than JPEG.
Panorama tools align overlapping fields of view, often with feature matching and blending to hide seams. Top-Bottom Collage simply places independent images one under another with optional solid gaps—no alignment, no lens distortion correction, no exposure blending. Use panorama software when scenes continue horizontally; use this tool when frames are conceptually separate slides in a vertical essay.
Browsers limit total canvas pixels to protect stability. SynthQuery surfaces guidance when your width, heights, and image count multiply beyond a safe budget. Lower the target width preset, shrink the gap, or remove a frame. For archival megapixel masters, downscale in Image Resizer first, then stack the web-ready versions.
Visit /free-tools for the full utility hub and keep https://synthquery.com/tools bookmarked for calculators, SEO generators, and AI writing products. If stacked screenshots accompany marketing copy, run Grammar or SynthRead on the text. If AI-generated imagery is in the mix, review disclosure policies alongside the AI Detector. For motion variants of the same ordered frames, open GIF from Photos; for PDF deliverables, try PNG to PDF merge.