I've had a lot of people ask me how I do the decals. I use waterslide decal paper, Not sure where I got it, google it and you can find it easy enough. The I just use Microsoft Word or any other similar program to type the lettering in whatever font I want to use. For the pics, such as my little Scottish Longbowman, I just paste the .jpg and resize it until I get one that fits on an arrow. The print it on your computer printer.
I originally got this through Tester's, the plastic model company. Its the same paper as the decals that go on their model cars. They also sell this spray that seals the printer ink. To apply the decals, after the sealer dries, you just cut them out and soak 'em in water for about 15-20 seconds, and slide them off onto the arrow. The sealer is necessary to keep the water from making the inkjet ink run.
Smooth the decals out with a fingertip to get any trapped air out, and after they dry, I seal 'em in with a coat of water based poly. I think oil would work too,but it tends to be a little yellow, whereas the water based dries real clear.
You are limited only by your imagination and computer savvy as to what you can print and apply to arrows. Once done, you can't tell its a decal at all. I found keeping the decals small is easier to get them into the position you want.