Let’s start with the basics. What is GIMP?

GIMP is

• an acronym for GNU Image Manipulation Program
• Free Software
• a high-end photo manipulation application that supports creating original art from images;
• a high-end application for producing icons, graphical elements of web pages, and art for user interface elements;
• a platform for programming cutting edge image processing algorithms, by scientists and artists;
• user-configurable to automate repetitive tasks;
• easily user-extend able, by simple installation of plug-ins

Adobe Photoshop on the other hand is a graphic editing program which is developed and published by Adobe Systems and is currently the market leading program for image manipulation. Since I installed Linux on my PC, one of the few programs that forced me to have windows installed, was Adobe Photoshop. I must confess that at the time I found Adobe Photoshop better than GIMP and irreplaceable. I gave GIMP a try but as an addicted  Photoshop user I could not replace it.

During my first months as a GNU/Linux user I started making second thoughts about using GIMP. “The free software is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech”, not as in “free beer”.” This is written on GNU’s official website and since GIMP is free software while Adobe Photoshop is not, I decided to give GIMP a chance.

You can find GIMP at it’s official website or just install it from your package manager or the terminal

$ sudo apt-get install gimp

One of the first things you should learn about GIMP is the user interface. In the video below you can find one of the easiest ways to understand GIMP’s GUI (I know the video is about GIMP 2.3 user interface but is very similar to the user interface of GIMP 2.6, if you have in mind a video of GIMP 2.6 user interface please post it on a comment).

You can also visit the GIMP Documentation website where you can find a good user interface manual. Here are the links:
1.Main window and main toolbox
2.Image window
3.Dialogs and Docking

For those of you that can not get used to GIMP’s UI, you can check out GIMPshop. GIMPshop is a modification of GIMP, intended to replicate the feel of Adobe Photoshop. (I never tried it though and I would be interested in comments on this one from someone who did).

But if you really want to learn how to use GIMP you should start using it and experiment. I know that most of you didn’t actually read the documentation above, I wouldn’t if I were you.

Let’s see some tutorials that you can start with. I placed the tutorials in an order so that the easiest are at the start.

Red eye removal: Easy tutorial to start with and also one of the reasons I use GIMP almost daily.

Changing Hair Color: Tutorial for beginners and a way to learn one use of the path tool.

Transform a new photo into an old one

Selective Decolorazitaion: Change certain objects of a colored image into black and white.

Lighting: Learn how to create a nice lightning effect. Once you know the basics, you can easily experiment to create different kinds of lightning.

Alter an image: How to remove things from a image.(a fast and easy image editing technique)

Contaminated Effect Find out how to use watercolor background at your creations

Create a twin It’s not as hard as it sounds! Really!

Smelting Text / Blood Text: Quify / Smelt text or other graphical objects

Create a signature: Signature for forums

Fun photo Manipulation: A little bit harder. If you already made the previous ones am sure you will make this one too!

After using GIMP for some time you might find useful to use some extra brushes. It’s the brushes that give something extra to your creations. Here you can find a fast tutorial on how to install brushes on GIMP. You can also download brushes here.

Fireball and explosion: An example where brushes can be used.

More tutorials can be found here for those interested:

http://www.gimp.org/tutorials/

http://www.gimp-tutorials.net/

http://www.gimp-tutorials.com/

http://www.pixel2life.com/tutorials/gimp/

http://www.noupe.com/gimp/30-exceptional-gimp-tutorials-and-resources.html

Conclusion

I know it is hard to make the switch from Adobe Photoshop to GIMP, but once you get used to it you will find that GIMP can replace Adobe Photoshop for your every day photo editing needs. I definetely reccomend it. It is after all a free software, and a good one too!