Once you start getting to work on a complex graphic, you’ll want to use layers. Here’s what I’ve found works best for me and seems to flow easily in GIMP. You can start with your own image, or download my classroom graphic here: classroom_small_zip.

To view the Layer’s dialog box, press CTRL-L or from the Dialog menu.

Create a new layer:

Notice that in the dialog box for a new layer you can select different options. I use the “Transparent” option most of the time, so my new layer will overlay the background layer. Also notice the size of the new layer. This is where it gets tricky in GIMP. Leave it at the size of the image right now.

Next, draw a new selection on this new layer and fill it with a color. When you click on a tool in GIMP, the dialog box below the tools area will change to allow for options with that tool. Experiment a bit with that and you’ll find some cool effects.

Once you have created a new shape on the layer:

Click to see a bigger version of this screenshot

Click on the Bucket tool and fill it.

Great! You’ve created a shape that’s on it’s own layer! Now if you move that graphic around it will float independant of the lower and upper layers. Oh, wait a minute – if you move it around you’re moving a layer the size of the entire graphic, not just the shape you made. This can really get you at the end of your design when you go to print or export – you’ll have a layer that is “over the edge” of the background layer. Trust me when I say, this is pure GIMP chaos.

So, just as soon as I’m happy with a shape for that layer I use the Autocrop Layer to resize the layer to just around my shape. Then, when I move the shape around, the layer won’t go over the edges of the main background layer.

Click for a bigger version of this screenshot

Choose, Layer and then Autocrop Layer. Voila! Now, the layer is exactly the size of your shape. What’s awesome about the Autocrop Layer is if you had multiple shapes and lines on a layer it would Autocrop to the edges of all the elements.

Experiment with this and you’ll soon see Autocrop Layer is your best friend when working with complex graphic layers.