Quite a few people still seem to have issues with getting their custom box backgrounds to work correctly so I thought I'd put this little troubleshooting guide and FAQ together to help. If you follow the instructions closely, you shouldn't have any problems.
If you encounter any issues that aren't explained here, please let me know. I will update this guide with any extra info or solutions as they are requested.
You can read more about customising your profile page here.
<div class="popup2-moremenu"><div class="floaty-boat"><img src="http://website.com/image.png"></div></div><div class="gr-box gr-genericbox">sample text</div>
Copy the code above and paste into a Custom box on your profile page. Replace the green text with your background