I can't import photos in GarageBand
If your media browser in Garage Band is only showing tabs for Audio and Movies, this means the first time you tried to use the Media Browser you didn't give GarageBand permission to access your Photos.

In other words, you would have had a prompt such as:



As you can see from the image above, you can still provide access after initially denying access by:


Going to Apple > System Preferences > Security &amp; Privacy
Select the Privacy tab 
Select the Photos app from the list of apps on the left
You should now see something similar to:





Now tick the checkbox next to GarageBand
If GarageBand is running, you'll see a prompt asking you if you want to Quit GarageBand now or later - select Quit Now.


Once you launch GarageBand again you'll see that Photos are now available within your Media Browser.