I'm kinda stuck here. Does anyone know?

You can paste your image(s) in paint and it'll tell you the size in the bottom right corner when you adjust the canvas size. A line of text = 10px, I think... and you can resize images using various software/webistes, but personally, I prefer to use Photobucket. You just need to create an account and upload your images then edit to resize them. ^^

Thanks! XD I just need to know how for Squiby:)