Screencap
From Fandom wank wiki
A screencap is an image captured from what a person can see on their computer screen. Now, since any big wank is sooner or later going to demand screencapping - as the original posts are soon to be locked, edited, and/or baleeted - here's how you can do it.
- Press the printscreen key (command-fn-shift-3 for Macs), paste and save the result in an imaging program, such as Paint. This is an excellent method for preserving a lengthy forum post.
- Or, File-->Save the webpage to your hard drive, and host it elsewhere on the internet. (Not a screencap as such, but close enough for government work.)
Then when the wank goes underground, you can cheerfully raise your hand at the perennial, "I was at work while this happened. Did anyone save it?"
Screencaps can also be images taken from movies and TV shows, but those are much more boring. Unless they involve wankers trying to figure out who touched whom where, or most infamously, fans of Blake's Seven analysing every screencap of the last episode to find a way someone could have survived. And of course, you can use them to make the bestest icons.

