A couple of years ago my kid took a funny picture of the cat and put some white text on it and said "look I made a meme!" I told her "No, you made an image macro. it's not a meme unless it goes viral." and even her mother who's older than me told me I was being pedantic and any picture can be a meme.
If you want to be pedantic, it'd be good to know that that's not what a meme is. A meme is a unit of cultural information—analogous to a gene being a unit of genetic information. A meme may not go viral, just like a gene might not be successfully copied onto other generations, but it's still a meme nonetheless :)
Yeah yeah I've read Dawkins :P My definition is based on earlier internet when things were what they were and became a meme as they were shared. Of course a popular image macro haz become meme but so can a questionnaire (wtf was wrong with us??)
A meme is just "A unit of cultural information, such as a cultural practice or idea, that is transmitted verbally or by repeated action from one mind to another."
Anything can be a meme. I mean, the entire first Shrek movie was a meme, just like the bee movie.