How can I decoupage on glass so that the glass can be rewashed?

I received some beautiful wrapping paper images that I would like to use on some plain white coffee mugs. Each image is about the size of a postage stamp, and I would only use 1 or 2 images per coffee mug. Does anyone know what type of glue and varnish to use? The mugs would be hand-washed, not to use in the dishwasher, but I don’t want the image to be damaged when the mug needs to be washed. I know how to paint on glass, but I am new to decoupage on glass!