on disk, so basically I'm trying to save the image of a solution and reuse it if the same quiz is required. So instead of recomputing the result just return the same image.

Got it. Is that cache surviving the crashes?

I'd have to host it somewhere (s3?). Right now I only commit the solution png to github. OFC it's not a good option but it's free and fast.

I think Cloudflare r2 has a generous free tier. You can also technically store images in redis I think. anyways, thank you for making this, really cool!

curious question from a non-programmer - are you checking against the exact same image (i.e. hashed), or is there an easy way of trying to match an image to a very similar one you've seen before?

Not OP, so I don't know what their website does, but there is a technique called "locality-sensitive hashing" that gives the same hash for similar items instead of exactly the same ones

https://en.wikipedia.org/wiki/Locality-sensitive_hashing