:33 < i am a pretty catgirl

guess

guess

Added some stuff to the script.

DS guy


Tio guy


Jetpack guy (really old but I like the sprite )

Paint.NET
It should be somewhat the same process in gimp...
Here's now in a nutshell:

Spoiler For lots of text:

1. Find a color scheme you like--be it blue, LOPN pink, or something as simple as gray.  Pick out three different colors, the base/normal color, one somewhat lighter (as if lights hitting it), one darker (as if it's in shadow)

2. Draw the sprite, on an 8*8 (or whatever) canvas.  Resize to 4x original size (32*32, normally) using "nearest neighbor" as resampling (keeps the blockiness). 

3. Say 1 is the base color, 0 is the dark color and 2 is the light color.  So if you have
1111
1111
1111
1111
beforehand, edit it so it's like
1222
0112
0112
0001
Basically, use the pencil to draw the light color on the top and right, dark color on the left and bottom.  Or change accordingly if you want the light to come from somewhere else.
For the lighting I have in these, leave the corners meeting in an up-left manner (and down-right) gray.  Look at the pictures above for examples.

If you're using the brush, make sure antialiasing is off btw.  Also make sure the background color is transparent or distinct from the three chosen colors, you'll need to differentiate them later.

4. Now re-size to what will be the final size, 128*128 or whatever.
Select everything but the background color that's hopefully different than the three colors in the pic.

5. Gaussian blur, fiddling with the radius until you like the result.

6. Make any finishing touches (transparent background, extra cropping, noticing mistakes and ctrl+z'ing back to step 3 to fix it, etc

            Done
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EDIT: used this, and a website, to animate the well-used Portal X sprite ^_^
http://i199.photobucket.com/albums/aa72/builderboy2005/dude.jpg