As I understand it, this library draws the image into a Canvas to then re-compress the Canvas' via the Browser's native `toDataURL('image/jpeg', quality);`. You can optionally specify a width/height to downscale the image.

Imho the readme needs to state what the library actually does. E.g.

"This takes a user image from a file input, optionally resizes it, and returns a JPEG, PNG or WebP as a Blob, ready to upload."

Agreed! I haven't looked into this at all but I wonder if you can run some algorithm on the datauri.

Lossy compression is still technically compression.

I got better results:

Input (original) name: the-northern-trifid-nebula-8499-1920x1200.jpg type: image/jpeg size: 737.26 KB

Output (compressed) name: the-northern-trifid-nebula-8499-1920x1200.jpg type: image/jpeg size: 263.17 KB (64.30% off)

I guess your original was more optimised than mine.

A tool like this should definitely check to make sure it has actually reduced the file size and, if not, just return the original with a note that it couldn't make any gains.

you should share an image link plus your settings/script to make this useful for OP

The result is dependent on your Browser. This library uses the Browser's native `ctx.toDataURL('image/jpeg', quality)` method to re-encode the image. The actual compression algorithm is not implemented in JavaScript.