How do i get rid of the mysterious white space after each image when sending a html email to hotmail client?

i've been working on a newsletter template to be send out to client with various email clients eg: yahoo, gmail, hotmail, outlook etc. All of the email clients work fine except for hotmail, each of the image seems to have a mysterious white space below it. Anybody knows where does this white space come from and how do i get rid of the white space? Thanks in advanced