You can create, edit existing photo,resize images and etc. with the help of this software, better read it's introduction and at the same time experiment with it, in that way you can learn from it.
If you're talking about editing a picture, it's a piece of cake. But drawing one from the ground up will take some know how and practice.
I've made hundreds of wallpapers in Photoshop my first ones were crap of course when I look at them today but I am not sorry that I made them like pricessa said, google for photoshop tutorials, even better is to search google images in my opinion because you will see end results right away like for example search for "photoshop blast text" in google images, or click the link bellow http://images.google.com/images?gbv=2&hl=en&q=photoshop+blast+text&btnG=Search+Images following that tutorial is a piece of cake, but you may have to search google again to find out info about functions in PS if you don't know some that are mentioned
yes of course you can make wallpapers from Photoshop. I think its the main tool to make one...i make my own wallpapers using it..
A good thing to know is to design it at the highest resolution you wish to create it for. Then it can always be scaled down. Some people make the mistake of designing at 800 x 600 then when they want to blow it up it loses quality.
you can even create wallpepers using ms pait but they will look much better if you use photoshop design them in a size of 1600*1200 and resize them for the smaller sizes
I believe the question must be related to the cost of photoshop. The OP may not have the software and the basics about the filters and all the other stuff packed to manipulate images and the such.
eureka....my first ps work.........please see n tell how it is.......http://soccergauge.blogspot.com/2008/08/english-premier-league-wallpapers.html
hm well not bad for the first one but I don't linke the colorsheme and it looks to empty... and if you look at it a second time even a kind of boring.
Literally U can do anything with Adobe Photoshop if u can use it features which are abandunt., name it and u will have the feature in it.. I like the software very much but i m not a pro though i can do my work easily..