There are many Photoshop tutorials out there with help on creating different finishes and effects. This one whizzes through one way of creating a Pop Art image.
I like the way he demonstrates very quickly with no messing around. You do have to watch his cursor closely to see precisely what he’s clicking on, because he doesn’t always tell you. But I have made quick notes to support this video which you can have to one side as well, whilst you chose your own image and work your way through the process. Give it a go – if you’ve got Photoshop that is.