If any file can not be deleted, then you can use the program LockHunter, which removes the active connections of other applications to that file, which allow you to change or delete file.
Pixlr is a free and probably the best web based image editor. I will show you how to open and and resize an image, I'm sure you will be impressed how well the web app actually works.
Nice little program that enables you to close all your opened applications and windows with one single click. It works in Windows XP and Windows 7 and doesn't need installing.