Okay, for starters... and even though many people have mentioned it, remember to save them as PNG instead of Bitmap or JPEG. :3
And by the looks of it, erm... I think, since you seem sorta new to this, I'd suggest working on recoloring more a little bit, since you still need a bit of practice on that... the Kirlia/Gardevoir one would be a good example. First off, when doing basic recoloring, it's best if you weren't to overwrite most of the tones with just one whole tone, which gives it a blank look. Try this: when recoloring, make a pallete (using the eyedropper tool, of course xD) of the original Pokemon's colors. See how the tones range from shades to highlights (and outline tones) are all... well, diffrent/seperate from one another (I'm sorry if I sound like I'm talking to you like a four-year-old. DX Not my intention)?
Now, just pick a color... any color you'd like, (even though though I definitely do NOT reccommend using the default Paint colors... however, seeing how it seems as if you're new to this, it'll have to do for now. Though, once you get the hang of things, try altering the colors, or just selecting your own colors in the Edit Colors > Define Custom Colors screen. =3). That'll be your base color. Now, if you can, apply/ "paint" the color beside what you believe is the base color of the pixel art. From there, still applying the colors beside the original colors, try to mimic the way the tones seperate from each other; go to the Edit Colors > Define Custom Colors screen, alter the lil' arrow by the bar at the very right to a darker or lighter tone of the color, depending on what's neccessary.
But that's just my reccommendation.... And sorry if I'm mentioning stuff that you may have already been aware of. I just kinda need to think as if I'm explaining this to someone who's never even done this kinda thing before, for some reason.
I hope I made sense. And most of all, I hope I helped a little.
Edit: Oops, I should've payed attention, too. Sorry! T_T Argh, I posted that all for nothin'. >.<; *facepalm*