While the API is built to handle very large images, it’s possible that you’ll run into some limits in certain scenarios:
All images: Uploads are currently capped to 150MB, just to ensure some joker doesn’t try and abuse the system. If you have a JPG you want to optimize larger than 150MB, just let us know. There is also a time limit of 5 minutes on all optimizations/conversions (I’ve yet to find an image that even comes close to 5 minutes).
JPG: The largest JPG image tested to date is 65.1 megabytes. If you are using the Lossy Compression option, which uses JPEGmini, it has a hard limit of 50 megapixels. Anything over that will fall back to Maximum Lossless Compression. Maximum Lossy Compression does not have a limit. The largest JPG image in the world is nearly a terabyte (stitched together from thousands of smaller photos), and there’s no way we could process that image, but anything your camera can produce, we can optimize.
PNG: Images in the PNG format are not very large in general, but depending on your server configuration, you could easily run into timeouts on your website with PNG images over 500kb. I’ve tested images up to 8 MB without any problems, but sometimes a 300kb image will take a minute or two to process.
GIF: The largest sample I have is 1MB, but if you run into any trouble with your animated GIFs, be sure to let me know.
PDF: The largest PDF tested is 83.8MB.
WebP: The format itself is limited to 16,383 x 16,383 (in pixels), so any PNG or JPG that fits within those dimensions can be converted.