Paid-for version: Adobe Photoshop
Open-source alternative: GIMP
GIMP is a package for creating digital images and manipulating photographs. It's been in production for 12 years and is compatible with most of the commonly used image formats such as JPG, TIFF, PNG, BMP and GIF, as well as most Adobe Photoshop and PaintShop Pro files.
The Good: It's no secret that many people download illegal copies of the enormously feature-packed Adobe Photoshop purely for cropping and resizing photos. GIMP takes care of this task without the risk of lawsuits. It's also got an array of tools for creating original raster graphics. The whole colour spectrum can be used with existing brushes or user-created ones, an array of filters and effects can be applied -- drop shadow being a popular choice. Once you've had some practice it's very easy to use and quickly proves itself to be a capable image editor.
The Bad: GIMP doesn't offer the extensive design and manipulation options that the £500 industry-standard Photoshop offers, though it has never aimed to. There really isn't any bad side to GIMP, considering what it's capable of doing. If you're used to editing images in Windows Paint, you'll need to spend a few hours getting to know it, but that's true with all applications that aren't aimed at children and the artistically backwards.
Conclusion: There's no need to
illegally download spend £500 on Photoshop if all you're doing is resizing images, applying fancy effects and cropping photos, because GIMP is extremely capable at these tasks. If you're looking for a career in design however, you might still want to keep saving for the Adobe standard.
Download it here: gimp.org