OK... So to upload, you go to "Horse pictures" on the tool bar @ the top where USER CP and Clubs etc is.
Then, click upload a picture, then browse - select the picture and make sure you choose a category for it.
Then if you want to put it on the post in a thread when you hit 'post reply' instead of using the quick reply there's a hyperlink on the right hand side under the smilies that says insert - and then find your picture in the category you chose for it

hope that helps!
I'll let you know about the bridle soon! Another member sent me one that's only 18$ LOL. But I'll think about it. Thanks!