Welcome!
What this guide is:
There's a lot to cover when it comes to image editing. Here I'm going to explain how you can make your very own avatar for use on the forums at gendou.com and anywhere else on the web using the free, open source image editing software The GIMP (GNU Image Manipulation Program). Of course, you can apply any of the techniques here to any other images as needed, like to make yourself a signature image or something for your profile.
Some parts of this guide will be written assuming you are using a version of Microsoft Windows as your operating system, version Milinnium Edition or later. Using GIMP will be the same on any platform though, so you should easily be able to use this even for OS X or Unix, so long as you are familiar with your own operating system enough to get along in the parts of this guide that are Windows specific.
What is The GIMP?
Well, that's a silly question! It's just the next best thing to Adobe Photoshop in photo editing. Oh, and did I mention, it's free?
GIMP is an open source project that has been around for many years. For those of you who don't know, open source only means that the computer code for the program is available to the public for free, and that instead of a company hiring a team of programmers to write a program to sell, the program is developed by individual programmers in their spare time, collaberating over the internet for the good of the common computer user. GIMP is by far, not the only program of this nature. Many other high quality (or some not so high quality) open source programs are available for free on the internet, such as the Microsoft Office alternative OpenOffice, or Stepmania, which I have also written a guide about. But that's beginning to go beyond the scope of this guide, so be sure to keep your eyes open for open source programs around the internet!
Getting Started
Step 1: Installing The GIMP (Windows Specific)
OK, so first off, you've got some downloading to do; two files to be exact. The latest build of GIMP for Windows is available here. You should first download and install the appropriate version of the GTK+ 2 Runtime Environment, depending on your version of Windows. After installing that, go ahead and download and install the latest version of GIMP.
Step 2: Getting Adjusted
The first time you start GIMP, you will be confronted by a happy little orange configuration wizard. You SHOULD be able to safely click through this without changing anything from the default values. They ought to work with just about any computer that can run its copy of windows decently.
Once you get GIMP through it's setup wizard you'll be brought to GIMP's usual setup. You'll likely see three windows: the tip of the day (read it if you want to), the tools window (and also the main window of GIMP. If you want to close the GIMP, close this window, not the other), and the layers window (but there's more to it than just your layers). If you're used to using Photoshop, dragging your tools to the left side of the screen and the layers to the right will put you in a pretty familiar place.
Whenever you open an image, it will open in its own window, so having lots of windows open will begin to make your Windows taskbar very cluttered, so be warned (of course, XP will group them for you)!
Basic Skills
Ok, lets get started. Open up an image and try out these things to get the feel of some basic manipulations. You can (almost) always undo your actions (usually all the way back to the orignial image) with the universal Ctrl + Z, so don't be too afraid to play around with things.
Zooming
In your face!
Of course you'll be needing to do some detail work at some point, so you'll need to zoom in on a part of the image. Easy enough:
Just hold Shift while you scroll the wheel on the mouse, or use Shift + '=' and '-' to zoom in and out. Use the scroll bars or clicking in with the mouse wheel and dragging to move about on the enlarged image.
Cropping
Just what you need. No more, no less.
First, click the first tool on the top left, the Rectangular Select tool. You can also use the keyboard shortcut 'R' to select this tool. Then, on your image, click and drag a box around the part of the image you need, leaving unwanted edges outside. Then click (in the image window) Image > 'Crop Image'
This will delete everything except for what you have selected. Nifty huh?
Scaleing
The art of finding the right size.
Let me first explain that scaling an image can be done either by you, in GIMP, or by the viewer's browser, once you put your image online (refer to my HTML guide on how to do this). The difference is, when a browser scales an image to a smaller (or larger) size, it's still downloading the whole image and then displaying it at a different size to the user. A large image sized to be a desktop wallpaper that is set to display as a tiny icon on a webpage will still take several minutes to load for someone on a dial-up connection. However, resizing it in GIMP (or another image editor) will take care of all of this beforehand and the image will only be as big as it needs to be.
To scale an image down in GIMP, just click (in the image window): Image > "Scale Image"
In an new dialog box, it will tell you the image's current height and width in pixels. You can ignore the other stuff in this dialog box. At Gendou.com, the height of avatars should be 25px or less, and signatures 100px or less in height, so enter an appropriate number for whatever you happen to be working on. GIMP will automatically adjust the width to match the height so your image doesn't get squished unnaturally.
Saving
So far you have all the skills needed to make your own avatar! All I do to make a simple avatar is Google Image search the anime character's name. Find a good image, select and crop just the eyes and then scale to a height of 25px. Once you're done with that, you'll need to save it and put it on your photobucket or perhaps tinypic or imageshack. Once safely uploaded, just follow the instructions in my HTML guide and get it in your profile over at the gendou.com.
Saving is fairly straight forward. Just click File > Save and you're on your way. The only point I'd like to make is that the format of the image is determined by what extention you give the name. In case you're unfamiliar with file extentions, they are a period followed by a three letter code that goes at the end of a file name that helps windows identify what type of file it is. By default, newer versions of windows hides these, but GIMP asks that you use them to tell it what format to save your file in. For your basic purposes, just add '.jpg' to the end of the name of your image. This is the JPEG format, it is very common, widely accepted, and quite friendly when it comes to filesize.
Last Thoughts
That's all there is to the guide so far, but I plan to extend it to teach how I add the blinking effect and give the bluish color to the image in the style of Gendou's and mine. Look forward to more updates!