photos will not allow printing

We would need the stuff that Yer_Man says to figure out what's going on. In addition, where did printing stop working? When you select a picture and choose File>Print (or ⌘P) do you get the print dialog, like this?

In the upper right (the red circle), does it have the name of your printer?

In the figure, I have already pressed the Print button (red arrow) and gotten the next dialog box. Does that happen for you? Does it correctly identify your printer (green circle)? If I were printing to a printer, I would hit the Print button here when the menu shows "Open in Preview" to get the final print dialog. But even if you don't have a printer connected (or it doesn't recognize it), you may be able to print to a PDF file. Can you choose "Save as PDF?"

Where in this process does it breakdown? Which button doesn't work for you?

Photos does allow printing. If you're having a problem with this you need to give us information: what you're doing, step by step, where it breaks down, any error messages, what version of Photos and the OS you have. Anything else you can think of that might be relevant.