Most emulators are able to export a PNG that you could then print with something like this project! They don't support using a webcam with the ROM for the Game Boy Camera though.

If you buy the real thing, there are lots of projects for extracting and printing the pictures though.

This project implements a fake GB Printer that you can then access via WiFi to download the prints: https://github.com/zenaro147/NeoGB-Printer

This project I wrote a while ago allows you to use a printer very similar to the one in this submission as an actual Game Boy Printer, connected to an original Game Boy: https://github.com/iamjackg/esp32-phomemo-gameboy-printer