HOW TO LINK ITUNES AND IPHOTO TO AN EXTERNAL HARD DRIVE , " NO MISTAKES GUIDE "
Solid Hard Drive space it's pretty expensive and actually, for me at least not even the most expensive one will be enough, downloading apps, music and making pictures became so easy that space is not anymore enough, at least for me taking pictures is something I do every day with my iPhone, the quality is acceptable and running out of space on your hard disk it's a consequence.
Two tricks I used to reserve my hard disk space to the real work are:
Put iTunes Library completely on an external hard drive or time capsule.
Put iPhoto Library completely on an external hard drive or time capsule.
BEAR IN MIND THAT TO NOT MAKE MISTAKES EVERY TIME YOUR OPENING ITUNES AND IPHOTO YOU HAVE TO PLUG YOUR COMPUTER TO THE EXTERNAL HARD DRIVE OTHERWISE YOU WILL AUTOMATICALLY SAVE AGAIN ON YOUR HARD DRIVE WITHOUT EVEN BEING ABLE TO NOTICE IT.
Go on your iTunes folder, could be on a mac under /USER/MUSIC/ITUNES
Drag an drop the entire library to the external hard drive.
Make a copy just for safety on an other hard drive ( optional)
Go on preferences
Click on advanced/Chose the library from your external hard drive
Click on consolidate library from the menu.
Make a copy of your iPhoto library located in /user/pictures/ photoslibrary.photolibrary (just as a backup)
Delete the photoslibrary.photolibrary file permanently
Copy the photoslibrary.photolibrary in the external hard drive