In the latest update Mac OS X 10.10.3. Apple rolled out their new desktop app “Photos” and introduced “iCloud Photo Library.” These changes have unfortunately broke the connection between Perfect Browse and the iCloud PhotoStream. Our developers are investigating solutions but we have no quick fix available yet.
The best way to edit pictures you are viewing in the new Apples Photos app is by dragging and dropping the thumbnail onto the Desktop or another local location. When you're done editing with on1 you can (in Finder) right click on the file > Send to > Photos app if you wish to re-import the edited copy.