iPhoto transfer

If I were to create a new empty photo library - would I lose all the photos I have in iphotos?

When I upgraded to High Sierra, I didn't realise my iPhoto was not compatible (not upgraded) so now I can't see my photos at all. I can see them in the pictures/iPhoto - package so they are still there on the computer.

I just thought if I create a new photo library and then I could transfer them?