Cloning with Gimp
Tutorial by: antonioVi
To start the tutorials on this Wiki, I will explain how the Group "Open Source Photography (OSP)" icon was made. It is a simple technique, but very useful to have as part of our digital darkroom skills, as it is the basis for other work we may want to execute. As it is the case of "Cutouts" and "Clones". It will also introduce you to the power of the gimp "layers" capability.
Starting from the end of the story, the icon was made from a simple crop of this cloning photography, using flickr icon tool:

Now let us see how I reached this point. I went with my friend and son Pedro, to Gulbenkina a famous park in Lisbon, where, by the way, one of the best Lisbon modern art museums is located. After going around for some time we found the ideal spot without too many people and with a cement block that could be used as a pedestal to obtain our final result. Here I have installed the tripod 50cm from the cement block, and at the lowest possible position, I wanted to give Pedro a "big head". I then put my Sigma 18-200mm at 18 mm and composed the scene. I took the following two shots of Pedro (in fact I took many more as I wanted to have different expressions to choose from, as in many Pedro was smiling a bit too much):

and

Now I was ready to go to my Digital Darkroom. In fact this is a pompous name for my laptop loaded with a lot of Open Source Software. Lets follow the workflow to achieve the final result. It is not long.
1. I start loading the first photo in gimp:
File > Open
I end with the first image in the bottom layer of the gimp "Image Window". It is worth remembering that every open image has at leat one Image window associated with it.

2. On the image window I do:
File > Open as Layer
And I put on the image window a top layer as follows:
3) If I now do <Control_L> on top of the image window, I get the layers window as follows:

We can verify that we have two layers in the image window. As a bonus you are learning some portuguese, as Camadas means Layers.
By Clicking on the eyes on the side of the layers you can get to see the top layer, the bottom layer or none.
4) Now let's get to work. I select the laso tool in the Toolbox

And start selecting the areas of the top layer which I want to remove. Once I have selected an area I do <Contro_K>. or if I want to go slower I can always do on the Image Window:
edit>clear

I continue using the laso tool to clear the top layer in the needed areas, this time to the right of the figure in order to start uncovering the figure of Pedro oberving his own head.

* story continues tomorrow - do not loose next episode. It is really thrilling :-)) *
In all cases like this I use layer masks to remove sections of the top layer. It has the advantage that if you "clear" an area you didn't mean to you just paint the mask white and the top layer pixels re-appear.