Hello,
I am a developer too!

I made https://instapics.2ix.ch/ - it uses clip to calculate correlations for text and images and can show them in a giant gallery. It needs some time to index images but the text to embedding works in realtime on a cpu. It can search images by image too, but only on images that are already indexed.

It can scan popular subreddits too, to search for a subreddit simply use r/[subreddit] as query like this: https://instapics.2ix.ch/?q=r/stuffoncats

It analyzes user interactions to find out what images a user likes and uses this data to recommend images in the home feed.
simplified it works like this: if one user likes content a,b,c and another user likes content a,c it is likely that he likes content b too.

It uses AI to compute alt text for images but this is really slow and only a few thousend images can be computed every day...

It does support user-uploaded content but it was removed from the navigation because it was not often used.