Performance is an odd metric to judge a database, not because its unimportant but because its mostly in the developer's court if they are configuring and access

Performance is an odd metric to judge a database, not because its unimportant but because its mostly in the developer's court if they are configuring and accessing data in a performant way. If the data is poorly indexed or queried its going to be slow no matter what database you use. Odds are the photos app is not configured well for your edgecase of having hundreds of thousands of photos. For the record I dislike SQLite - especially the cargo culting of SQLite by people who aren't even using it in production.