Do you have to register to see photos?
No, I think it's some kind of redirect shenanigans. Kinda how like on google.com the URL that's shown at the bottom if you hover over a link is not what you get if you click the link. There's some kind of switcheroo going on. For example, if you paste:
http://i561.photobucket.com/albums/...8-D41D-4C99-A03D-EEFDD160CFC4_zps34tmzqnu.jpg
into the address bar, instead of loading a .jpg image it redirects to:
http://s561.photobucket.com/user/tr...D-4C99-A03D-EEFDD160CFC4_zps34tmzqnu.jpg.html
It does this even with javascript.enabled;false but if I put the link in a file and load the file it works fine and simply displays the image. From there I can right click and View Image and it won't redirect (i.e. it shows the image, which I thought was the whole point of photo bucket). So, they're using some kind of browser "feature" I'm not familiar with. Safari doesn't do this, btw. Thanks for the input!