to save space on my ssd, i removed iphoto. I now want the app back, but do not have an optical drive nor an external drive to use to install with the disc. I do however have everything backed up on an external hdd with time machine. I tried dragging and dropping the app, which works, but I cannot open it. Some error dialogue comes up saying "iphoto cannot be opened because of a problem. Check with the developer to make sure iphoto works with this version of max osx. You may need to reinstall the application. Be sure to install any available updates for the application and mac osx." Any ideas on how I can make this work?