Another free editor for windows is Paint.NET It does not have all the scripting and filter function of The Gimp, but definitely can do a lot, and worth checking out.
Don't forget about IrfanView. Although it is primarily a viewer it does have some cool editing features. It also has very robust meta data features.
Oh, and then there is XNVIEW, free also, and great for batch resizing.
I personally have found my investment in Adobe's products very worthy, but these programs are truly useful and can really help if money is tight.
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