At home window clings

OK so I watched this YouTube video from the early 90's that showed you how to make your own window clings. The video did not specify what kind of paint to use so I bought so fabric paint from Oriental Trading Co. and it didn't seem to work so well. But the tips were not exactly what I needed I think. Anyways here's the deal: print out or use some pictures from coloring books. Any image you want but I think ones that aren't filled in will work best. Place them into a page protector. I bought a 25 pack of Avery, the brand supports box tops for education which my children turn in at school so, BONUS! :) Place the picture in the sleeve and just paint over it. When dry the paint should peel off and have a bit of tacky stick to it so it will stick to the window. Now the video said to outline the picture in black, but I did not do this. I am also trying to do fireworks so I realized that the whole thing wouldn't connect so I'm not sure how the final result will be. I also can not say how long they will last as far as sticking to the windows. If anyone has any tips or a better way to achieve this project feel free to share. My 2 that I did are not quite dry yet so I will post later as to how they turned out for sure.