It's not a version issue for Android File Transfer.
That worked reliably until one day Apple updated OS X just one more time, and then we started seeing problems that come down to individual Mac hardware/software <--> phone versions. It's happening across all Android.
There's a for-pay Mac solution, but the easy way around the problem is to try AirDroid. It's free and secure on your home network.
Groups of pictures will go into a zip file in your Downloads folder.