Here's a tissue paper method: https://www.youtube.com/watch?v=ca1pD2sx_M0
You could glue it to the outside of a jar using a non-flammable adhesive such as E6000.
Hi Yo: If it's a photograph, it may crack when you bend it around the candle jar and permanently ruin your photo. I'd try to make a colour copy and use that. Wet it slightly so that it bends without making folds, and place it on the jar. Use rubber bands to hold it until it dries. Then, remove the picture and attach it with E6000, which, when dry, is heat proof. Good luck
Glue it on
Printing photos on to vellum paper then sticking that to the glass works really well due to it's translucency