Irfanview

This is a light-weight program for most of your photo viewing needs.
Features : View, Optimize, Scan and Print, Create Slideshows, Batch Processing, and more.

GIMP

GIMP is a professional level image editing program, similar to Photoshop (expensive).
Hundreds of great tutorials are available by searching on Google, and don't forget Video Tutorials
on Youtube!

Blender

Blender is a free, open-source 3D graphics creation suite. Same as with GIMP, search on
Google and YouTube for Guides and Tutorials.