Request: Add status of images to prevent hammering API

GiantBomb has a strict “Non-commercial use only” policy it seems.

I’m working on a mobile application which will centralize all your favorite gaming news, streams and videos. In the streams part, we’ve got a list of games, shown with their box art (I wrote “cover” because it’s the API name).

Our current problem is that loading all those images over redirects can take a noticeably long time on mobile, especially with a bad connection. We just want to have local default instead of Twitch defaults, the problem is simple.
The current solution is that our backend has to send a HEAD request for each link provided by the API, one by one, and check if it redirects. We have no idea if there is a limit on those links at all. I know that there is no real rate limiting on the API, but we limit ourselves to 1 request per second. But those links aren’t part of the API? Can we hammer them?

It would be so simple if the API didn’t return a default silently, and provide a default image somewhere else instead.