GIMP (GNU Image Manipulation Program) is a powerful image editor with a lot of functionality, being one of the free alternatives that most resemble the known, but not free, PhotoShop.
Gimp has several functions: retouching digital photos, resizing photos, rotating and cropping, various settings (such as brightness), ability to add special effects, also removing elements from a photo, combining several images , etc.
Changes applied to an image can be saved in different formats (JPEG, TIFF, GIF, PNG, TGA, PSD, and BMP among others), not necessarily the original format, so it can also be useful for converting images.
With this design software it is also possible to create drawings, logos and animations. Like Photoshop, Gimp includes a system of layers, masks, gradients, paint brush, rectangle and ellipse tools, hand-held tool, and many more options that designers can use.
The GIMP supports the incorporation of plugins to further expand the number of functions, with hundreds of them available, such as: Liquid Rescale, an intelligent resizer that keeps the scale of the photos avoiding distortions; Save for Web, to achieve images of good quality reducing as much as possible its size; Watermark, to add watermarks to photos; And many more extensions.
Gimp 2.8.20 is the latest version, updated in February 2017. It is free and is available for Windows 8, 7, Vista and XP; in Spanish. On the official page you can find versions for other operating systems.
Version 2.8 features a fresh, more friendly and modern interface. Now you can export the projects to other formats used by other graphic editors (GIMP by default uses the XCF format). It also includes new tools, which contribute to it already considered one of the best and most complete programs in its field.
From the official website, a complete Gimp Spanish manual is provided, which details the operation of each of the tools that can be accessed with this application.