This makes no sense at all but I was fighting with this issue the same as a number of you it seems. I decided to give up on the Photoshop app instead and see if I could get done what I needed to do in Photoshop Express. When I opened a photo in Express it asked me to choose my photo allowance preferences, I set that on Allow All in Photoshop Express. I randomly had the thought, 'I wonder if the preferences are linked?' Went and opened the Photoshop app back up and I could import photos now. Hope this helps someone else fighting with the same issue!