photos keeps losing imported photos

I just bought my Mac and am having problems using eBay and Garagestore.

When I import photos off my camera into Photos they appear to be there when I look through the Photos app. But when I try and access them from eBay or Garagestore then they're not there in the Last Import album where they should be. Am I doing something dumb? I really need to be able to import and use the photos using the Photos app, it's an important part of my business.