Hi Conched! Welcome to RS!
I'm an apple user and use photobucket as well. Here's what I do to share an image...
If you are in your album in photobucket, there is a box on the left side titled "Share this Image" with fields labeled 'Email and IM', 'Direct Link', 'HTML Code', and 'IMG Code'. If you highlight the 'IMG Code' Field (it's a web address that is bracketed with IMG in square brackets on each side - something like IMG]http://i994.photobucket.com/albums/af63/Shamus_reefer/IMG_1431.jpg[/IMG although the first and last IMG will also be enclosed by square brackets, and copy and paste that into your text box, it will link to the picture on photobucket. I also commonly resize my pics to 600 x 800, although I haven't tried any of the other sizes here in RS.
Hope this helps!