Right now if two documents alternate loading the same no-cache image URI, we'll keep revalidating it, because the aCX passed in won't match the key stored in the image cache entry. This apparently actually bites gmail composition when the user attaches an image: for some reason they have two documents in play that alternate trying to load the image. We should consider including the aCX in the cache lookup key instead or something.... Or storing in the cache a list or hashset of aCx values for which the image has been validated?

Seth, do you have time to deal with this, or know who does? I realize imagelib is a bit undermanned right now. :(

I do not expect to have time to deal with this for the next few weeks, although if some free time appears I'll keep it in mind. Timothy, would you be able to take a look at this more quickly?

I don't think I'll be able to get to this in the short term either. :(

Oh, one thing I forgot in comment 0: gmail is hitting this. If you're composing a message with an image in it, we hit the situation from comment 0 every time they auto-save the message, causing us to download the image several times per autosave. :(