I used the same concept to build a searchable database of YouTube thumbnails in my watch history. I always end up trying to remember a video I didn't finish from a week or two ago and YouTube's history search plain sucks. So I built an app that tracks all my watch history across all devices, downloads the thumbnails and runs them through a local Gemma model to write a paragraph description and OCR any text in the thumbnail.

Currently at 30,000 thumbnails described, basically 2 years of watch history. Search is via FTS5 in SQLite and works great on an 8 year old MacBook Pro.