When I try to share my pictures in iPhoto, I get this error message: “Other users will not be able to access your shared photos because port 8770 is being blocked by your firewall software. Please disable the firewall for this port and restart iPhoto.” Is there a way to share my pictures across my home network from behind the safety of my firewall?

Yes, you can leave your firewall turned on. You just need to open the problematic port.

Go to System Preferences > Sharing > New. In the window that appears, change the selection in the drop-down menu from Port Name to Other.

In the field labeled TCP Port Number(s), type 8770. For the description, type iPhoto Sharing. The field labeled UDP Port Number(s) remains blank. Click OK and restart iPhoto.

You should now be able to share your pictures across your network while enjoying the protection of OS X’s built-in firewall. Remember that your other Macs need to have sharing turned on in order to access the pictures you’re trying to share.