If you copied photos to your iPod using the full resolution option, enable disk use, open your iPod in Finder, open the photos folder then open the "full resolution" folder and drag the photos out of that folder to your desktop. For enabling disk use look here.
Disk Use.
If you only copied the photos as thumbnails, you can't do this so you'll need a program such as this one.
iPod Photo Liberator. (both Mac and Windows versions available)
Photos as thumbnails won't be of the original quality when copied back to your computer.
For your contacts:
1. Make sure iPod is set up to be used as an external hard disk (as above).
2. Connect iPod to your computer. The iPod appears as a hard disk on your desktop or in a Finder window.
3. Open the iPod hard disk.
4. Open the folder named "Contacts".
5. Find the vCard for the contact you want to move.
6. Drag the vCard to the desktop.