The best way to resize pictures is...

[Blockoman]

what? It seems anything I find just screws up the quality. Boy, I wish the forums' max avatar size was 100x100...

[Ad Bot]

[Ghøst]

Paint.Net

[dkamm65]

Use paint.net, but make sure you keep it a png with quality to auto-detect.

[blockybob]

heres a good GIF resizer. its pretty cool, I used it for mine
http://www.smiliegenerator.us/gifresize/index.php

as for pictures, I just usually use Gimp, I just crop the part I want most, then resize it, it doesn't lose much quality at all, paint.nets good too

[Blockoman]

Well, mine are PNG, so I guess I'll use gimp.