I've had the Fragment app (fragmentapp.com) from Pixite (pixiteapps.com) on my phone for a long time, and still enjoy playing around with my phone images of skies, water, and similar "backgrounds" to overlay their shapes and adjust it with filters... I have a few favorite templates/adjustments that I make over and over, and always seem to turn up something that would like nice as a sticker...
Of course I have a tiny sticker printer... Sheesh. You suspected, didn't you?
