As stated in the title, this tutorial should enable you to make a banner in 30 minutes or less. I will be using Green Bean's avatar to demonstrate - thanks Green Bean! ^^
This tutorial is set in MS paint, a.k.a the default paint program in every computer/laptop. Because some of us don't have photoshop and the other programs that others have.
To find this program, click start at the bottom of your computer screen.
Go to sub-menu 'All programs'. Look for 'Accessories' in the sub menu that opens up. Hover over it with your mouse.
Another menu opens up. Look down it. You should see a program named paint. Click, and follow the instructions shown below.
Copy. Then paste into paint program. Your avatar will have a black background. The next step shows you how to fix that.
Take note of the dark-ish red/maroon boxes and arrows.
See the bucket like tool? Click on it and scroll down, then choose the color white. =3
Then follow the arrow and click the black area. You'll get your avatar normally, without any black background.
Now click the dotted rectangle tool which I circled in red.
Look down to the second red circled thing below the toolbox. Make sure the blue section is on the bottom symbol. Drag a large dotted triangle round your avatar.
Then right click on your now white backgroundish avatar with the rectangle still round it. Click copy.
Move to another paint page WITH YOUR BACK GROUND ON IT.
Click the same dotted rectangle tool and right click on your back ground where you want your avvie to be. Click paste.
P.S. This background does NOT belong to me.
Legend:
Red/Maroon boxes - Take note of whatever is in it : Tools, colors.
Red/Maroon arrows - They tell you where to move things, or where to click.