Besides sewing, I love to paint. Although my hands don't work as well as they used to, I can still manage simple designs. But I wanted to be able to decorate my jars beyond those simple designs, so I set about looking for a decoupage medium that would withstand washing. I purchased Martha Stewart Multi-Surface Durable Gloss Finish decoupage medium, grabbed a cup from my cupboard, and set about decorating a mug for testing. The label on the decoupage medium claims that once completely cured, the finish is top-rack dishwasher safe. I don't have a dishwasher, but I've hand washed this mug a couple of times...looks good to me!
I tried it out on an old jelly jar, and a wooden box I had. I think those came out pretty cute. The dots on both the mug, and the jar were added with an acrylic paint pen.
I had a few pieces of heavy scrapbooking paper that I used for parts of these...the rest is done with wrapping paper. The Dollar Tree is a great place to get wrapping paper, and if you're willing to spend a little more, American Greetings makes a reversible wrapping paper. The wrapping paper is thinner, and can be a little more challenging to work with, but I was able to cut all of those flowers out of a small piece of the wrapping paper.
If you'd like to just paint your jars, any acrylic paint will do. Painting on glass is not the easiest thing to do, but if you stick to simple designs it goes much easier. Also, keep a wet paper towel, and a wet q-tip handy to "erase" your mistakes. To make your paint permanent, let the paint dry for 24 hours or so, bake your piece in a 350 degree oven for about 20 minutes. Let the piece cool in the oven. Don't bake your decoupaged pieces -- if you're mixing paint with decoupage either bake before decoupaging, or put a final coat of decoupage medium on the piece after painting.