Whilst the majority of them aren't particularly funny, this application of the word 'meme' makes perfect sense within both the dictionary definition and Dawkins' original usage:
"an idea, behavior, style, or usage that spreads from person to person within a culture"
Thanks! It's pretty silly, really, but it has been fun to play with. I only got switched to 'production mode' by Sincerely on Sunday, so I have yet to receive any of my test postcards - but their main business is printing people's photographs, so I think they should be fairly acceptable quality.
A meme is a cultural unit. It can be an image or video, but also a belief or idea. It's like a gene, but in culture. So a "funny image with captions" might be a meme, but that neither means that every "funny image with captions" is a meme, nor that you can send all kinds of memes with that page. Thus the description is wrong.
I dont think that word means what you think it means, and I think you should google it.