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Photoshop Tutorials
Here is another great site to gain more insight into using Photoshop by using his tutorials.
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Programming Art: 10 Things to Know About Photoshop
This is a list of 10 things everyone needs to know about Photoshop including keyboard shortcuts and how to make specific images such as stars.
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Graf X Design: Paint Shop Pro Tutorials
A great collection of Paint Shop Pro tutorials. Topics included for this low-cost alternative to Photoshop are water marking photographs, magic of masks, transparent gifs, different types of buttons and more!