Merge images
Combine images into one side-by-side strip.
This runs in your browser. Nothing is uploaded.
About Merge images
Lays several images side by side in a single horizontal strip on a canvas in your browser, with every slot sized to the largest image you loaded.
Side-by-side comparison is the common case: a before and after, three colour options for a client, a run of screenshots that has to travel as one file because the other end accepts one attachment. Doing it in a design app means opening a design app and setting up a document. Doing it on a random website means uploading work that is frequently not yours to upload in the first place.
Every image you load is measured, and the widest and tallest dimensions found become the cell size. The output canvas is that cell width multiplied by the number of images, by the tallest image's height. Each picture is then drawn at its own resolution into its slot, anchored to the top-left corner. Nothing is scaled. Anything narrower or shorter than the largest leaves transparent space to its right and below.
There is no scaling, no gap control and no vertical or grid arrangement, despite what a collage tool would usually offer — the layout is one row, left to right, in the order the files were selected. Mixing a 4000-pixel photo with a 400-pixel screenshot therefore produces a strip that is mostly empty space. Resize your inputs to a common height first, and name them so they sort the way you want.
How to use Merge images
- 1Select several images at once, or drop them onto the panel together.
- 2Check the order — images are placed left to right in the order they were added.
- 3Click Apply to build the strip and see it in the preview.
- 4Click Download to save the combined PNG.
What it won't do
- Horizontal strip only — no vertical stack, no grid, no spacing between images.
- Images keep their own dimensions; nothing is scaled to a common size.
- Output is PNG, so a strip of photographs makes a large file.
Common questions
Can I stack images vertically instead of side by side?
Not on this page. It produces a single horizontal row, and there is no orientation switch. For a vertical arrangement, put the images into a PDF with one per page, or use the sprite sheet generator, which packs them into a near-square grid rather than a strip.
Why is there empty space around some of my images?
Because every cell is sized to the largest image in the batch, and smaller images are drawn at their native size in the top-left of their cell. A 400-pixel image sharing a strip with a 4000-pixel one gets a 4000-pixel-wide slot. Resizing everything to matching dimensions beforehand removes the gaps.
How do I control which image goes first?
Order follows the order the files were added. The most reliable approach is naming them so they sort correctly — 01-before.jpg, 02-after.jpg — and selecting them together, since your file picker hands them over in sorted order. There is no drag-to-reorder step after loading.
How many images can I merge at once?
The code sets no limit, but your browser does. Canvases have a maximum total area — a few hundred megapixels on desktop Chrome, considerably less on mobile Safari — and a strip of twenty full-resolution photos will exceed it. If the result comes back blank, that ceiling is why. Resize the inputs down and retry.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation