Are photos really mnemonic devices? I mean, you could certainly have a visual mnemonic device, but a simple photo is just a photo. A mnemonic is usually some kind of trick...
I can't say you're wrong, but I can't say I'm convinced either...
If you'll excuse the analogy, the mental picture that came to mind was someone pining over their ex and taking longer to get over breaking up with them because they keep pictures of them around.
I can't say you're wrong, but I can't say I'm convinced either...