Download and install the OneDrive app. I do this to backup my photos to OneDrive. Just open it now and then so it backs up photos you take in the future.
On a Mac try opening iPhoto and going to File>Reveal in Finder>Original File. Then if you have OneDrive in Finder, I'm assuming you could copy and paste from there.
On an iPhone you should be able to open the OneDrive app and upload photos from your camera roll. I'm not sure how iPhoto would play any roll in that.
There was also another way by going into show package contents but I dont remember where to find the pictures after going into show package contents.