Since I've fielded this question a couple of times now, here's a quick how-to on finding your direct link.
A direct link/hotlink is a link to your photo all by itself, nothing else on the page. It should end in an image extension, like .jpg, .png, or .gif. (My camera saves in .jpg; I think most do.)
Your direct link should not lack an extension or end in .html.
On a service like Photobucket or Tinypic, the hotlink is listed as "direct link" or "direct link for layouts". If you're using a service like Picasa, you can right click on the image you want to use and select "copy image location" - that image location is your direct link, and what we need in the email.
The reason for the hotlink is that we always put up an image of each outfit on the blog here, and in order to make that image appear directly in our entry, we need a hot link.
If it doesn't end in an image extension, it's not a direct link.
If clicking on it doesn't take you to the image all by itself, like this, it's not a direct link.