Deleting multiple photos from the grid

Hello, thank you so very much for responding. The problem was that Shift+Click wouldn't select more than three rows. He figured out that using the Zoom to shrink the photos enabled him to get about 300 photos on the screen and then Shift+Click worked. We were able to delete about 20,000 photos from the grid in one day. Thanks very much for your help, all!

Just tried it, and the shift click works on my computer after scrolling (interestingly NOT 100% of the time). You can try to change the zoom factor at lower right such that you can see more rows, which you can then delete.

Also if you can filter all the photos, you can then use Ctrl-A to mark all that you want to delete and then right click-delete.

What exactly is the probem?  I know almost nothing about Macs, but you should be able to click on the first photo for deletion, scroll down to the last consecutive/contiguous photo for deletion and then Shift+Click on it.  If the photos are not consecutively arranged in the grid, you should be able to Cmd+Click on each photo to select them for deletion.  And if you have both consecutive and non-consecutive photos for deletion, you should be able to keep your finger on the Cmd key and also use the Shift key when you need to select the consecutive photos.  (At least, that's how it works in Windows using the Ctrl key instead of the Cmd key.) 

You can also use the Zoom control to show more than 3 rows in the viewable grid.