Found something old today
Photoshop is nice, even if you know how to draw. That shirt design has a very neon appeal to it. The dash is a nice touch!
I've made 3 shirt designs for the shop I work for that I did with pen, but I go through them on photoshop after they are inked for doing the color layer separations and center sights in the corners, for screen printing.
Photoshop is fantastic for converting photographs into B&W halftones, in the correct LPI (lines per inch) and row degree arrangement controlled, so it looks good on shirt thread count (threads per inch). They can't be close, because it will cause a moiré problem, which is where the thread count and dot count cross up and cause lines or patterns that are unwanted.