Just don't save the resized image as your PSD file or thats all you'll have to show for your efforts! (i know, i've shot myself in the foot with this before!)

I always "save" first to make sure all my modifications are saved then i make my JPG file, then i resize my image by setting the "crop" tool to 200px by 200px and crop the image. This allows you to move and resize the crop for the best possible thumbnail before you hit the enter key. This is better than showing the whole image reduced (adds a little mystery to it ;)). You can undo the crop by deselecting it in your HISTORY palette, or don't save the changes when you close the file.

:)
retrocity