Actually, I make them myself. I purchased a packet of "water slide" paper online. It comes in 8.5" × 11" sheets so it fits into my color ink jet printer easily. I download clip art or other images online, resize and modify them on my desktop computer using Photoshop and then print them out onto the water slide paper.
I do not coat the inside of the bowl with any kind of chemical protectant, but fortunately the bowl wood is much denser than the ground-up weed that sits in it. As long as you don't leave the flame on the bowl for an extreme amount of time, it will not ignite - after all, you don't want to over-heat your weed when smoking because that will destroy the THC and your lungs. I've found that after a few smoke sessions, the bowl gets coated with resin and creates a natural protection.
