(this post shall be used to continue the tutorial- link on first post)
This trick has several ways to be performed, but this is the way I recommend- especially for sprite sheets, which is rare in pokemon anyway.
1) use eyedrop to select color you want removed. Set as color 2
2) make/select the color you want to replace, set as color 1.
3) make a large box of the color you want to replace the color selected as color 2.
4) set as trans-select, move sheet or w/e.
There was a thread made about a different way, using the eraser tool, but I tend to find that this method can lead to error. Remember to use sprite towers, folks! It makes the process a lot easier.
The spray-paint tool
It's sucks. It's NOT for coloring, it's NOT for writting, hell, I don't even know WHY it exists. PLEASE DON'T USE IT!
Difficult Colors: Yellow and Brown
I've been noticing lately that people REALLY don't know about yellow and brown.
First of all- Brown. The good brown shades are kinda hidden, but they genearally fall into the specified range.
And now for yellows. People seem to have this WEIRD disability that like... stops them from knowing how to coordinate colors... Well this is something I recomend for making yellow sprite towers- DON'T USE THE SAME DISTANCE! Yellows change VERY fast as you add more and more shading, so try to do them semi-exponentially.
If you do the same distance from each color, you end up with
A) something that looks like practically the same shade over and over or
B) An over-jellified sprite. that's when it takes a color, and there are so many subtle shades it... looks like jelly.
ONE last note with yellows- TRY using the cream-shades. They work VERY well and prevent the sprite from looking gaudy.
FireFox and Transparencies
If you're one of the many smart people who've switched over from Internet Explorer to Firefox, then you've probably noticed when you copy/ paste from the net a image with a transparency, it pastes as BLACK insted of IE and AOL's white. This can be a problem in POKEMON sprites, as they actually USE that shade of black. This is a simply solved problem- all you have to do is "print screen" the page, and crop out the image.