Having just gone through the pain myself of trying to figure out what’s the proper cover photo size/ratio for Bluesky, I thought I’d share my findings and the helper image I created for it.
It’s worth briefly mentioning: Bluesky is new(ish), still in development, and a lot of things that should work one way just don’t. Much of the platform has not been shared publicly, and some of these items have fallen by the wayside, but are still important to many users. I’m posting this January 9th, 2024, so this could definitely change (and probably will) in the future.
My findings
Bluesky has a bunch of different display sizes, actually. On the app, the cover photo is one size. On mobile web, it’s another (360×150), and on desktop, it’s a completely different uploader altogether (598×150). This isn’t anything new, as we’ve been seeing this happen on Facebook for years. Still, knowing what ratio(s) to design for is important.
You also have to provide a square image for some reason, so through my findings of trial, error, checking the source code, and various other means, here’s what I’ve come up with:
I’m still not sure what the size is for mobile app, but I have the ratio at least. If you focus all your assets into the middle then, fingers crossed, nothing will get cut off. I’ll update this as I learn more or the sizes change. Hope this helps you with your Bluesky cover photo!