Thanks Dave for the step-by-step. Let me add a suggestion if you are using Photoshop Elements (latest version is 4.0). This is usually available for under $80 at Sam's Club and Costco. $99 at most stores. It has almost ALL the features of the $$$ version of Photoshop CS.

One that almost always gives a more pleasing result is "Auto Adjust".

If you don't like the results, you can always UNDO it.

When you are resizing your images, remember to FIRST set the resolution to 72 dpi. THEN resize it (but only smaller number, not larger, as Dave has said.)

You can protect your originals from being overwritten accidently by setting their property to "READ ONLY".

Select all the original images in a folder, then right-click on one of them, then choose Properties and check the box "Read Only".