I have old photos in iphoto app but can't get to them

Hi. Any help please? I have 314 mb in my old iphoto app and I can't access these photos. The photos didn't migrate as they should have when I installed various updates (I'm now on iOS 9.3). I don't know how to access these photos - I can't seem to access them when trying to open via pc (windows 10) and using any of the apple software. And I can't access the info by just looking at the phone's storage. Apple are puzzled and looking at this for me but does anyone have any ideas they can help me with please? Thanks a lot.