Layers: Understanding how they work

It has recently come to my attention that a tutorial on the various functions of the layers palette and how layers work, could be very beneficial for any beginner in Gimp. To That end I have created this. I hope it helps anyone to easily understand the basics of the layers in Gimp. Also, I know it is referred to as a "dialogue" in gimp. The two terms are synonymous. I am used to the term "palette", and that is the terminology I will use. Sorry if this causes any confusion.

1-Run-down of the Layers palette
Below is a diagram of the layers palette. Click on it to see a larger version of it. Look it over and then we'll move on.



2- Copy and Paste an image from one file to another in gimp
Copying and pasting an image from one file to another can be a bit confusing. Just follow these steps.

Open the image to be copied, and the image to be pasted into. Below I have a nice cutout of a T-rex skull that I will copy, then paste into the image of the T-rexon the left. Simply make sure the active window is the T-rex skull. Type Control+C to copy the cutout. Then click on the other window to be sure it is active. Type Control+V to paste the skull into the new image.


3- Copy and paste cont.
Looking at the image, it appears that the skull was successfully copied. But we're not finished. Notice there is a selection around the skull. Also, looking at the layers palette, you'll see that it's layer isn't a layer yet. It appears as a 'Floating selection'. The easiest way to make it a new layer is to click on the 'new layer icon' in the lower left corner of the layers palette. Whahla! you have just successfully copy and pasted a new layer into your image.


4- Layer masking and Layer modes
You'll notice I made a few alterations to the image below.
I altered the Layer mode of the skull to 'difference'.
On the T-Rex image I created a layer mask, then using a Black to white gradient, I used the gradient tool to cause the fading affect.
After this I created a new white layer and moved it to the bottom. The white allows the skull to show up the way I want it to.
If you're unsure how to create a layer mask please refer to my tutorial called 'Layer mask basics', for full instructions on how to create a layer mask. They are amazing!


5-Using the anchor icon
Lets say you wanted to readjust the position of an element on a cutout or an image without creating a new layer. To do this create your selection of the element to be adjusted. Cut the selection by typing Control+X. Then select none by going to the 'Select' menu and clicking 'None '. Then type control+V. Using the 'move' and/or the rotate, and scale tool (depending on what you want), reposition the newly pasted floating selection. Now click on the 'anchor' icon at the bottom of the layers palette. The floating selection has now become a permanent part of the layer directly below it. If you wanted to create a new layer out of it click the 'new layer' icon instead. The image below shows you how I have repositioned the T-Rex head a little before I anchor it.


Conclusion
That about covers the basics of the Layers palette. If you have any questions about any of the icons I didn't cover in detail, let me know. I'll be glad to help out.

I may be updating this in the near future. The next version of Gimp will include additional options in the layers palette.