Vertical lines in printed image

Thanks so much, everyone! I was able to get another photo that worked better, but these tips will help immensely if (and likely when) this issue arises in the future.

I suspect the same. If this photo was scanned from a printed piece, it will have a bit of the printed halftone dot pattern in the scan, and when you print this, the halftone patter of your printer conflicts with it. To minimize it, try smooth out the original scan ("descreen") by opening it in Phostoshop and applying a couple of filters. I'd start with Filter > Noise > Median, starting with a low number and increase it until you see the dot pattern disappear. You can also try Blur. Either way, there's a balance between when the filter helps you out and when it starts to affect the clarity of the photo, so you need to try a few settings and find a happy medium. Then, try and print it again.

Note: the moire effect changes between printers, so even if you find a good setting for your own, it may be completely different on another printer.

I agree it looks like a moire problem. You can sometimes correct that by rotating the image slightly in the frame.

 It looks like a moiré effect caused by conflicting screen patterns.