Photoshop is a Pain

It's been a while since I've made any icons (years maybe), but I've run into a problem I think I used to fix with a border but is now causing me problems. I use Photoshop CS3 and whenever I resize my image down to 100x100 I get this little 1px line around the image that is slightly transparent. Needless to say I don't know what to do about it. Any help would be appreciated, a reference picture under the cut.




It's hard to see but is especially noticeable on the darker parts, such as the area I've circled in red.