How would you go about using your iPhoto library on multiple Macs and three or four locations? I have a client that has: - iMac in office - iMac at home - Macbook Air - Macbook Pro - iMac at home in Europe - Macbook Pro in Europe - MobileMe subscription His current library will be about 40 Gb. My thought was to keep his iPhoto Library file on an external hard drive and carry that around with him. He would simply Option-Click when he opens iPhoto on whatever machine he happended to be using and open the iPhoto Library off the external drive. I can think of several problems with this approach, not the least of which is backup. Maybe he should sync it to each machine he uses it on. There's probably some better solutions out there. Open to any and all suggestions.