I have some photos in the DCIM folder on a MicroSD card that normally lives in an Android phone. When I mount the card on my Macbook Pro using a USB card reader, Photos.app automatically launches. But the app doesn't seem to "see" that there are pictures inside the folder. I can access the pictures through the Finder (see screenshot), and of course I can manually import the pictures by dragging them from the Finder window into Photos, but I am wondering if there is some way I can point Photos.app to the directory where the photos are stored so that it can find them and import them on its own.
I just stumbled upon the same thing, and am also seeing the same effects that nicedog reported:
Also if you select "Import" from the menu and select your microsd card, all folders on that card are grayed out.
I've found a slightly strange workaround, though, that will allow you to use Photos' Import feature with the grayed out folder entries. Open File>Import, choose your device, and when you come upon a grayed out folder, right-click, and choose "Quick Look". This will pop up another window which you can close, but once closed, you'll see that the dialog will have traversed into the folder that was grayed out. You can continue doing this until you reach the sub-folder that you want to import.
Painful, but it's at least a way to use the import feature instead of drag/drop.