[xml]

I also implemented a batched client-side web tool to resize photos to a certain file size (in a few hundred lines of JS). It only supports JPEG, but it resizes photos almost instantly https://randomforest.net/resizePhoto.html

Here are a few ideas to make yours faster:

1. Use the browser's canvas element to compress JPEG or PNG images instead of WASM. The libraries which come with browsers can use processor-specific instructions, while WASM only targets the smallest common denominator of the most common architectures, so it will be slower.

2. Which resizing method are you using to find a fitting image size? For me, it worked well enough to downscale by some factor a few times until it fits, but if you want to get super close, you could use binary search.

[mnutt]

My experience has been that using canvas to resize images produces inconsistent results from one browser to another, and in most cases is higher file size and lower quality than other tools. Enabling imageSmoothingEnabled helps, but is only supported in chromium-based browsers right now:

https://caniuse.com/mdn-api_paintrenderingcontext2d_imagesmo...