Combine Images produces a single PNG file, not a multi-page PDF, by arranging 2 to 12 local raster images horizontally, vertically, or in a centered grid inside the current browser tab. The phrase "combine images into a PDF free" covers two genuinely different jobs, and the distinction matters before you pick a tool. Some readers want a real PDF document where every selected image becomes its own page; others want a single flat image that visually stitches several photos together and can be saved, shared, embedded into a slide, or posted to social media. Combine Images does the second job, arranging local raster files into one PNG with a configurable gap and background color, while never uploading the source files to a server. The PNG output is not a compromise. PNG keeps every decoded pixel sharp, supports transparency in the inputs, and opens in virtually any image viewer, chat app, or design tool, so a flat PNG is often a more practical deliverable than a multi-page document for contact sheets, storyboards, before-and-after comparisons, and step-by-step screenshots.
What "combine images into a PDF" actually means
Two free workflows answer the same search phrase and produce noticeably different files. The first is a true PDF document, where each image becomes its own page that you can scroll, print, or attach to email. The second is a flat image, where the chosen pictures are visually stitched into one rectangle you can paste, post, or embed. Combine Images does the second job, and that is the right answer whenever the goal is one shareable picture rather than one printable document. The tool lays out exactly the images you select, in the order your browser lists them, so sorting your files before upload gives you the placement you want. Once decoded, every picture keeps its original pixel dimensions: nothing is resized, scaled, or cropped, and the Canvas drawImage primitive documented on MDN preserves the source pixels rather than resampling them. For a real PDF with one image per page instead of a flat PNG, the matching tool is Image To PDF, which runs in the same in-browser style.
How Combine Images places your files
The tool applies three deterministic layouts to the files you select, in the order your browser lists them. Horizontal placement lines every picture up from left to right at its decoded pixel size; the output width becomes the sum of every input width plus the gaps you set, and the output height matches the tallest image, with shorter pictures centered vertically inside that height. Vertical placement uses the matching rule top to bottom: the widest input width is kept, narrower pictures are centered horizontally inside that width, and the gaps appear between rows.
Grid placement follows a fixed, predictable rule. The tool takes the ceiling of the square root of your image count to pick a roughly square column count, then arranges every cell so its bounds equal the widest decoded image for width and the tallest decoded image for height. Each source is centered inside its cell without stretching, cropping, or changing its aspect ratio. Empty cells in the final row and any unused cell space are filled with the background color you picked, which is exactly how the gap-color setting produces clean padding between tiles.
Combining your pictures in the browser
- Pick between two and twelve supported raster images in the order you want them placed. The browser file picker preserves the selection order the tool will use.
- Choose a layout: horizontal, vertical, or centered grid. Set the gap in pixels from 0 to 100 and pick a six-digit background color (a normal hex like #FFFFFF) for the canvas and any empty cell space.
- Click Combine images. The tool validates each file's size and codec, decodes the pixels in the current tab, and calculates the output dimensions from the layout rules described earlier.
- Read the displayed output dimensions so you can confirm the canvas stays inside the 8192-pixel-per-side and 32-million-pixel area limits before you download.
- Download the generated PNG. The file is produced by the browser's standard PNG encoder, as HTMLCanvasElement.toBlob on MDN describes, and contains the merged image at the exact dimensions shown.
Supported inputs, output behavior, and file limits
The Combine Images tool accepts PNG, JPEG, WebP, GIF, AVIF, and BMP, the same set of raster formats a typical browser can decode. SVG is deliberately rejected because it can reference external resources or contain very large render instructions, and keeping this workflow restricted to raster inputs makes the result predictable. Each source file must be 25 MiB or smaller, all selected files together cannot exceed 100 MiB, and the combined canvas cannot exceed 8192 pixels on either side or 32 million pixels in total area. Those caps are there to keep memory spikes from crashing the tab, so a giant photo library needs to be split into batches.
Animated GIF, WebP, or AVIF input contributes only the single frame the browser decodes along its image bitmap path; animation is not preserved in the static PNG output. Files whose extension looks familiar can still fail when their bytes are corrupt or their codec is unsupported, and that error is a validation result rather than an upload, so reopening or re-exporting the source is the fix.
The output is a PNG written by the browser-required encoder. PNG preserves sharp pixels and any transparency present in the decoded input, but because the background is painted before the images, transparent regions in your sources become the chosen opaque background color in the final file. The tool does not compress toward a target byte size, does not add metadata, and does not preserve EXIF, color-profile tags, animation, layers, or original filenames. For print production or color-managed compositing, verify the exported PNG in dedicated software before sending it to a printer.
Combine Images vs Image To PDF
The two browser tools solve adjacent tasks, and picking the right one saves a step. The table below compares their inputs, layouts, output formats, processing location, and the situations where each one fits best. If your real goal is a printable PDF with one image per page, see the separate walkthrough on turning multiple images into one PDF in your browser.
| Aspect | Combine Images | Image To PDF |
|---|---|---|
| Image count | 2 to 12 raster files | Variable batch into a PDF |
| Layout | Horizontal, vertical, or centered grid on one canvas | One image per page, in original order |
| Output format | Single PNG | Single PDF document |
| Where it runs | Current browser tab | Current browser tab |
| Animation handling | First decoded frame only | First decoded frame only |
| Best for | Collages, contact sheets, social posts, slide previews | Printable PDFs, scanned archives, page-by-page sharing |
Use Combine Images when you want a single flat composite you can paste, embed, or post. Use Image To PDF when each image needs to stay a separate, full-resolution page inside a real PDF document.
Getting the cleanest combined PNG
A few practical habits produce a result that does not need fixing in another editor. First, sort the source files in the order you want them placed before uploading, because the tool keeps the order it sees from the browser. Second, pick a background color that matches where the PNG will land: white for slides, a brand color for marketing assets, while keeping in mind the canvas is never transparent because the background is always painted first. Third, raise the gap for visible borders between tiles, or set the gap to zero for an unbroken strip. Fourth, watch the displayed output dimensions to confirm the canvas is inside the 8192-pixel limit, especially when stacking many tall portrait images vertically or many wide landscape images horizontally. Fifth, plan logos or overlays knowing that transparent pixels become the chosen background color in the merged file rather than relying on transparency in the output. Sixth, for printable or color-managed work, open the exported PNG in dedicated software to confirm the result before sending it to a printer or a design tool, since the tool does not embed ICC profiles or EXIF.