Chat Glitch.... swapping photos.

Last night another provider posted a photo in chat... and another member and myself both saw MY photo I had posted about an hour earlier.

Tonight, I posted my pic, and that other provider's picture showed on my screen. Other members said they saw the picture I actually sent over chat.

I have screen caps of both ....

What's going on?

EDIT: It seems that both photos had the same file name. Simple numbers. After a renaming of the files, the issue was solved. Now I am curious as to how long photo's posted in chat are stored/cached.