My CEO, Brian, uses a picture of himself in his email. The image is hosted here: http://i49.tinypic.com/2uol63m.png (tinypic is a Photobucket company)

Looks lively, attentive, and friendly... right?

Gmail image cache of the image returns a cat: https://ci6.googleusercontent.com/proxy/se_iEEzdxzy1wRbMk8xXJhM7C7jqp2RyINhqPoq8Ybbn4P6yi0FqdB9RXMq-iat9ut2pNofWz7o=s0-d-e1-ft#http://i49.tinypic.com/2uol63m.png

Not the same person...

Now Brian's emails (including emails to investors and all previous emails he's sent) contain a cat sleeping on a couch instead of a goofy smiling face.

Dig into the guts of the problem: When you visit the image (http://i49.tinypic.com/2uol63m.png) with a browser, you get Brian's smiling face. Download the same image with wget and you get a sleeping cat! Looks like Photobucket/tinypic is changing what they return based on headers and Gmail image cache doesn't send the same headers as my browser.

IT GETS WORSE!!!!

Another image in Brian's email signature (which used to look like his name signed in cursive), has ALSO been replaced with a selfie containing quite a bit of cleavage!

Lesson learned: those "unique" image file name hashes are actually recyclable!