That's probably a combination of me being lazy since I need to do 8 of those images -_-, the crappy source quality of the images (seriously, all those things are jpgs and once you zoom in there's color bleeding EVERYWHERE), and the low resolution of the source images which makes deleting 1 pixel actually quite noticeable =/.
Edit:
Actually ya, after dropping a black background on them (something I need to remember to do -_-). It's very clear that what you see is actually just discoloration of the character's outline caused by jpg's darn compression routines messing with the colors of nearby pixels. Rather than delete those pixels I just need to airbrush them to the outline color to correct -_-. I need to get better quality sources -_-.