Scottish slang. Can be used to describe someone who is making a complete cunt of themselves. Once hearing being called this they should shut their trap (mouth)
"Hear, did you see that roaster oan x-factor the other night?"
Resizing an image larger to fit on many pages. These are then printed out and placed side by side to recreate a large poster of the original image. Usually the image is also modified to be made up of smalldots, similar to old comics.
"That poster is huge, it must have cost you hundreds."
"No, Wendy taught me about rasterbating, it only ended up costing like $10."
The Rasterbator is a web service which creates huge, rasterized images from any picture. The rasterized images can be printed and assembled into extremely cool looking posters up to 20 meters in size.
The origonal definition for rasterbator was completly wrong, so I stole the one off the official site... google... duh