custom wallpapers/happy mail

i really, really want to make my own custom mail or wallpaper but it's so complicated. i downloaded GIMP 2 and iDmakeDL2 v2.0.0.20, but i don't understand the "create image" part, how do i even start creating a a room background or a mail? with gimp? and how do i resize it or save it into a BMP file

please help

Assuming you're using a Windows-based computer: launch Paint. It's built into Windows. The location depends on which version of Windows you have. Generally it can be found at Start / All Programs / Accessories / Paint. Once Paint is open you'll see a large white rectangle (your canvas). It's easier if you start with the right sized canvas. Click properties and type in the correct width and height (128 x 72 for wallpaper), or grab the lower right corner of the canvas and drag it towards the upper left until the size shown in the status bar at the bottom of the Paint window shows 128, 72. Yes, it's small. But you can zoom in on it using the magnifier scale (lower right corner of the status bar) or by holding down the Ctrl key while you rotate the scroll button you your mouse. Now, simply draw the picture you want to use as the new wallpaper. When done, save it, then open it in Gimp, convert it into a 4-bit indexed / 16-color BMP file, and save it again. (Use a new filename, so your original artwork isn't lost and can be touched up if the converted picture isn't as nice as you expect it to be.)