i photo keeps crashing unexpectedly

Every time I open my i photo, for past few days, it let's me look at a few images then crashes unexpectedly, I don't know what I can do. I have very slow Internet so downloading big files is a problem, I haven't been able to download el Capitan which might help.

I doubt upgrading will help. You can try launching iPhoto holding down the command and option keys together to bring up a diagnostics dialog: try each step from top to bottom and see if that helps.

I tried that but after the first step i photo quit!