Close
Not scraping anything either, but I like to download pics I happen to like.
TBH it seems kinda random. Doesn't seem to be recency-based - I had some month old fast pics and week old slow ones, or ID-based. Saw instances of pics from the same set (adjacent IDs and upload dates) alternate between slow and fast.

On the slow end it pretty consistently floats between 100 and 200kb. But the downloads almost never fail, so I'm not that bummed out.