Merge Images Online
Processing entirely on your device — large files may take a moment.
Drop the images in queue order, pick a direction, and every photo is scaled uniformly to the shared dimension (smallest height for side-by-side, smallest width for stacked) before being placed edge to edge — nothing is stretched and nothing is cropped.
The output is PNG, so screenshots with transparency and diagrams keep their crisp edges. Perfect for before/after comparisons, step-by-step documentation and screenshot threads.
How to merge images
- 1
Select your files
Drag & drop your JPG files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to PNG". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted PNG file individually, or grab everything at once as a ZIP archive.
About the JPG format
JPG (short for JPEG, the Joint Photographic Experts Group committee that standardized it in 1992) has been the default photo format for over three decades. It compresses photographs using the discrete cosine transform: the image is split into 8×8 blocks, and details the human eye is bad at noticing are discarded. The result is files many times smaller than uncompressed data, at a quality level you control when saving.
In practice JPG is unbeatable for photographs and smooth gradients — camera memory cards, messaging apps and the web all assume it. It is a poor fit for screenshots, logos or anything with sharp edges and flat color, where compression leaves visible ringing around text. There is no transparency support, color depth is capped at 8 bits per channel, and every re-save with compression compounds tiny generational losses.
+Strengths
- ✓Opens on literally every device, app and browser made in the last 30 years
- ✓Compresses photos dramatically — typically 10:1 or better with little visible loss
- ✓Quality level is adjustable, so you can trade fidelity for file size
- ✓Mature ecosystem: EXIF metadata, ICC profiles and progressive loading all supported
!Limitations
- −Lossy — artifacts appear on text, sharp edges and flat areas
- −No transparency, so overlays and logos need PNG or WebP instead
- −Repeated re-saving at low quality permanently degrades the image
About the PNG format
PNG was created in 1996 as a free, open replacement for the patent-encumbered GIF, and it has been the reference lossless image format ever since. Pixels are compressed with the DEFLATE algorithm (the same one inside ZIP files), which reproduces the original image exactly — bit-for-bit — while supporting full 8-bit or 16-bit alpha transparency. Screenshots, logos, icons, charts and anything with text or sharp edges should live in PNG.
Because it never discards information, PNG files of photographs are several times larger than JPG — that is the price of perfection. Modern PNG encoders add filters per scanline that make screenshots and flat-color graphics compress surprisingly well. PNG also became the base of APNG, the animation extension that browsers play natively.
+Strengths
- ✓Truly lossless — every pixel survives exactly as it was
- ✓Full alpha transparency with smooth edges, not 1-bit masks
- ✓Open standard, unpatented, with excellent tooling everywhere
- ✓Ideal for text, line art and flat-color graphics — sharp edges stay sharp
!Limitations
- −Photographs become several times larger than JPG
- −Base format has no animation (that is the APNG extension)
- −16-bit or high-resolution PNGs can grow very heavy
Frequently asked questions
How are different sizes handled?
Every image scales uniformly to the shared dimension (height for horizontal, width for vertical), keeping its aspect ratio — no stretching, no letterboxing.
Can I control the order?
The queue order IS the merge order — first file leftmost (or topmost). Remove and re-add to rearrange.
Why PNG and not JPG?
PNG is lossless and keeps transparency, so merged screenshots and diagrams stay pixel-exact. For photos where size matters more, convert the merged PNG to JPG afterwards.