Photo Editing Applications

I normally use IrfanView as a program to resize and sharpen digital images.

http://www.irfanview.com/

I also normally use Easy Thumbnails to create small versions of images.

http://www.fookes.com/ezthumbs/overview.php

Fotografix is a portable image editing application.

http://lmadhavan.com/software/fotografix/

Another free option would be Paint.NET.

http://www.getpaint.net/