Stitch images together
Joins several images into one. You can choose horizontal, vertical or grid layout, the gap between images and the background colour.
How to use it
- Drag your .png .jpg .jpeg files onto the area above, or press "Choose files".
- If options are shown, set them as you like. They appear below the file list.
- Press "Convert". The conversion runs on your device, shows its progress and can be cancelled at any time.
- Press "Download" next to a result. With several results, "Download all as ZIP" gets them in one go.
The formats involved
PNG .png
PNG stores images without loss (W3C PNG Specification, Third Edition, Recommendation of 24 June 2025). It also defines colour types that carry a transparency (alpha) channel.
Typical uses: logos and icons · screenshots · images that need a transparent background
JPG .jpg .jpeg
JPG (JPEG) is a format for compressing continuous-tone images such as photographs. The international standard (ITU-T T.81 | ISO/IEC 10918-1) defines DCT-based lossy processes and, separately, lossless processes; the usual photo mode is DCT-based, so the compressed image can differ from the original.
Typical uses: storing photos · photos shared on the web and in messengers
What changes in this conversion
- The image is re-drawn before it is saved, so metadata such as camera data (EXIF), location and colour profile is not copied into the result.
Limits and things to watch for
- On a phone, large files can be slow or fail because of memory limits.
- The file size that can be processed depends on your device. The limit for your device is shown in the drop area, and files above it are refused with a message.
- The browser reads the image once, draws it into a canvas and saves it again. Browsers and devices implement JPG decoding differently, so the same file can give very slightly different pixel values.
- Browser canvases have size limits, so very large images are reduced to a safe size. On iOS we conservatively assume about 16.8 million pixels (16 MP); WebKit raised its limit to 8192x8192 in 2024, earlier versions were limited to 4096x4096.
FAQ
Is my file uploaded to a server?
No. Conversion happens only inside this browser, and file names, contents and results are not sent to our servers. Some converters download their conversion program (code) the first time you use them; your files are not sent then either. See the privacy page for details.
What happens to the EXIF (camera) data and location of my photo?
This converter re-draws the image before saving, so EXIF, location and colour profile are not in the result. If you need details such as the shooting date, keep the original file.
Does it work on a phone?
Usually, with a current browser. Very large images are reduced to a safe size because of browser canvas limits, and the conversion can fail if memory runs out. This converter uses conservative limits.
Why do semi-transparent parts of a transparent image look slightly different after conversion?
As found in testing, the browser stores pixels as 8-bit values with transparency multiplied in, so semi-transparent pixels can shift slightly through rounding, and the hidden colour of fully transparent pixels is lost. Opaque pixels stay exactly the same.
Sources and check date
- W3C: Portable Network Graphics (PNG) Specification, Third Edition
Abstract (lossless storage); colour types 4 and 6 (alpha) · 2026-11-10 - ITU-T T.81 | ISO/IEC 10918-1 (JPEG)
Scope; 3.1.82-3.1.84 (lossless / lossy definitions); the text contains no transparency (alpha) channel · 2026-11-10 - WHATWG HTML Standard: the canvas element (toBlob)
toBlob(callback, type, quality): default image/png, quality for variable-quality types · 2026-11-10 - WebKit bug 271002: Increase the limit on the canvas size to 8192x8192
iOS canvas limit was 4096x4096; raised in 2024 · 2026-11-10 - QOI specification 1.0 (qoiformat.org)
14-byte header (magic qoif, big-endian width/height, channels 3|4, colorspace 0|1), 8-byte end marker, un-premultiplied alpha · 2026-11-10
Date we opened the original documents ourselves: 2026-11-10. Specifications can change, so read the original again before anything important.