Well, one bright and sunny day in the PKMC RP channel (that's a lie; it was raining hardcore and murky as heck), we were doing a few conversations where every few seconds some actions between characters would confuse others since none of us really have individual character heights down. For instance, a lot of the characters resemble the natural heights of their species, so while a lot are usually under four feet, others can be as tall as nine feet. We all started joking around, saying that there should be a height meme or something to help sort it out.
I took the joke too far.
The idea is that you take the template, either the PNG or the PSD format, and you draw in your character and two or three other people that your character knows. The point is to show height differences and in turn make it clear how everyone sizes up in the long run. If you want to adjust the height scale or expand the image to show more characters off at once, well, Photoshop is definitely your friend.