Increase image-size constraints (post embeds, user profiles) and served resolutions

[pfrazee]

We need to improve the quality of images a smidge more. Here's my proposal:

• app.bsky.embed.external#external thumb:
  • maxSize 300,000 ➡️ 600,000
  • maxWidth 1000 ➡️ 2000
  • maxHeight 1000 ➡️ 2000
• app.bsky.embed.images image:
  • maxSize 300,000 ➡️ 600,000
  • maxWidth 1000 ➡️ 2000
  • maxHeight 1000 ➡️ 2000
• app.bsky.actor.profile avatar:
  • maxSize 300,000 ➡️ 600,000
  • maxWidth 1000 ➡️ 2000
  • maxHeight 1000 ➡️ 2000
• app.bsky.actor.profile banner:
  • maxSize 500,000 ➡️ 750,000
  • maxWidth 3000 ➡️ 6000
  • maxHeight 1000 ➡️ 2000

This is roughly a 2x of all limits. For the image-proxy serving, we also 2x all the limits and we revert the thumb sizing away from "fit" (as that wrecks the ability to serve wide images).

I suggest if we want to consider any higher limits that we look closely at the costs -- not of image storage or bandwidth, but specifically of transfer latency in the federated network. The reason we're being stingy is to ensure that peoples' feeds load in a timely fashion when the extra hops of federation are introduced.

[dholms]

I'm wondering if we should go even bigger for embeds? Like up to at least a MB. Just from a quick survey of twitter, they have a lot of images that are greater than 600 kb. As Jake pointed out, these are gonna be insubstantial in comparison to videos.

I expect most images to be served off of a gateway that does some processing, which means that the images only really have to make a couple hops: client -> pds -> BGS (which then serves it off the gateway).

From the gateway, we don't have to serve the full resolution image, but I think we should give the clients some more wiggle room in terms of what they upload.

[pfrazee]

I'll let yall make the call here, just want to make sure we get it right. If you're not worried about the latency of 1mb then go for it.

[dholms]

kk @pfrazee wanted to check in on

we revert the thumb sizing away from "fit"

what's the desired behavior here for thumbs? They're already set to cover which === fill. Is that right? Or do we want inside which === fit?

[dholms]

Oh actually I see, that was a recent change from https://github.com/bluesky-social/atproto/pull/495 that hasn't made it to prod yet 👌