The detail work she does is printed on thin vinyl.
Best solution I've found. By the time I bought the stuff to do the print on decals myself, made sure I had the appropriate graphics software to produce what I wanted, and did all the work, it's easier and cheaper to send Callie a picture and get an envelope in the mail. Some people that are graphically inclined may enjoy the work and handle the software every day to make it an effective solution.
I have a vinyl cutter and I have the graphics software and I still order things from her I couldn't be bothered messing with.