Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Image Merger
- Home
- Utility
- Image Merger
Combine multiple images into one. Merge horizontally, vertically, or in a grid — all in your browser, no uploads needed.
Drop images here
or click to browse
Supports JPEG, PNG, WebP, BMP, GIF • Max 50MB each • Min 2 images
What is Image Merger?
An image merger lets you combine multiple images into a single image. You can arrange them side-by-side (horizontal), stacked vertically, or in a grid layout. This is useful for creating before/after comparisons, photo collages, image strips, or combining screenshots.
This tool runs entirely in your browser using the HTML5 Canvas API. Your images are never uploaded to any server — they never leave your device.
How to Use This Image Merger
- Upload images — Drag and drop images onto the drop zone, or click to browse and select multiple files (at least 2, max 50MB each).
- Choose merge mode — Select Horizontal (side by side), Vertical (stacked), or Grid (rows and columns).
- Adjust settings — Set the gap between images, background color, grid columns, and output format.
- Preview — See a real-time preview of the merged result before downloading.
- Download — Click Merge & Download to save your combined image.
Frequently Asked Questions
How many images can I merge?
You can merge at least 2 images. There is no hard upper limit, but for practical purposes we recommend up to 20 images. The tool runs entirely in your browser, so the limit depends on your device's memory.
What merge modes are available?
Horizontal places images side by side from left to right. Vertical stacks them from top to bottom. Grid arranges images in rows and columns — you can set the number of columns.
What happens if images have different sizes?
In horizontal mode, all images are aligned to the center vertically. In vertical mode, images are centered horizontally. In grid mode, each cell uses the maximum width and height of the images in that row/column. The background color fills any empty space.
Is this tool safe to use?
Yes. All processing is done in your browser using the HTML5 Canvas API. Your images are never uploaded to any server, stored, or logged. Once you close or refresh the page, no trace of your images remains.
Last updated: 17 Aug 2026
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