Resize an animated GIF

This tool changes the dimensions of the whole animation. A 640 × 360 GIF resized to width 320 becomes 320 × 180. Height rounds to the nearest whole pixel, with a minimum of one pixel. Aspect ratio can therefore differ slightly for very small outputs. Enlarging an image cannot restore missing detail.

Each supported frame is composed with its original disposal and transparency instructions before resizing. The new GIF keeps the frame count, encoded delays and loop extension, including a missing loop extension for play-once files. GIF delays are stored in hundredths of a second. Zero delays remain zero in the file, but browsers and other viewers can impose a minimum playback delay or override looping.

Smaller dimensions often help file size, but this tool does not target a kilobyte limit and does not guarantee a smaller file. Re-encoding writes complete composited frames and new palettes. An efficiently optimised original may become larger even after resizing. Check the downloaded byte size when an upload form has a strict limit.

GIF supports a palette of at most 256 colours per frame and on-or-off transparency. Resizing and palette quantization can change colours, add banding or make partially transparent edges opaque or transparent. The encoder uses no dithering. The preview shows the new encoded result; this is not a lossless animation edit.

Compressed bytes, source and output canvas dimensions, frame count, cumulative frame pixels and encoded output bytes are bounded. Large animations can exceed a phone’s safe workload even if their compressed file is small. Plain-text GIF extensions, unsupported disposal modes, malformed data and truncated files are rejected. Reduce the source dimensions or frame count in another editor if it exceeds the limits.