This tutorial makes use of the free online image editor http://pixlr.com/express
Go to http://pixlr.com/express
Select "Open URL" and enter one of these urls:
Click Adjustment button - Add Image button (left side of menubar).
Add your image to Cascade by doing New - yoursite - then selecting this new .jpg file and fill in the Display name and title - cutdown images are automatically generated by Cascade.
Another resource for Timeline cover photos is:http://timelinecoverbanner.com