You can also scan all your stickers that will fit on a page together, then use your magic wand tool to get rid of the white background (if there is one) and save the whole document with the multiple stickers as a png file. Then when you needed one of the stickers, open the png file and use the selection marquee tool, copy and paste it onto your layout page.

A png file would be smaller than the psd file (I think) and it would have transparency.

__________________
Clara Wallace
Matter of Scrap

When eating a fruit, think of the person who planted the tree.
-Vietnamese saying