Images to GIF

How Images to GIF works

The image is decoded into a canvas element, redrawn, and handed back as a new file. A canvas lives in the tab; closing it discards the pixels, which is why nothing needs deleting afterwards. Nothing is re-encoded on a server, so no copy of the original survives anywhere you cannot see.

That is the whole architecture: static files, one script, no upload endpoint to leak or log. Close the tab and the work is gone.

A GIF is a palette, not a video

The format dates from 1987 and stores at most 256 colours per frame. Every frame is quantised to that palette, which is why a photograph shows banding while a screenshot or a logo comes out perfect.

The encoder does two things worth knowing: it builds the palette per frame (so a mostly blue frame keeps its blues), and it can store only the pixels that changed between frames. A static background therefore costs almost nothing, which is why screen recordings compress far better than camera footage.

Frame timing and looping

Delay is stored in hundredths of a second per frame. 200 ms is a slideshow, 80 ms looks like motion, and anything under 40 ms is rounded by browsers into something faster than you asked for.

The loop flag is a single number in the file header: 0 means forever, -1 means play once. This tool writes 0 when the loop box is ticked, so the animation repeats for everyone who opens it.

Why encode in the browser

An upload-based GIF maker has to receive every frame, encode on a server and send back a file that can be several megabytes. Doing it in the tab means the photos never leave the device and the finished GIF is written straight to disk.

The work runs in a Web Worker, so the page stays responsive while the palette is built.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions