Animated GIF and WebP Size Capacity

How big can my animated GIF or WebP be and still be automatically resized?

As a rule of thumb: a 1280×720 animation should stay under about 290 frames (roughly 20–30 seconds at typical export speeds) to resize correctly. Some other common sizes:

Animation size	Max frames	Roughly this long
1920×1080 (Full HD)	~129	~9–13 sec
1280×720	~291	~19–29 sec
800×600	~559	~37–56 sec
500×500 (thumbnail/social size)	~1,073	~72–107 sec

The limit is about frame count relative to dimensions, not file size in MB.

What happens if an animation is over the limit

The image-resizing library we use (Sharp) won't process an animation whose total size (frame width × frame height × number of frames) exceeds about 268 million pixels — it's a safety limit built into the library itself, not something we added. When that happens, the Lambda code serves the original, full-size file instead of a resized version, rather than showing an error. If you need a properly-scaled version of something this large, trim the frame count or dimensions at the source.

Why this limit exists

Sharp is built on libvips, which documents a default 268,402,689-pixel processing limit, and treats an animation as every frame stacked into one tall image for that check. This is a well-known, documented behavior with Sharp (reference), not something specific to our setup.