Ok so first you are going to need to go to a image sharing website such as tinyurl.com or photobucket. Ill use photobucket as a example since I use this often
(http://i1299.photobucket.com/albums/ag69/Youshallfearme2/be5a907e-b1f2-46bc-8ed6-21ef6ea30650_zps7aa4084c.jpg)
Click into photobucket and search up the image you are wanting.
(http://i1299.photobucket.com/albums/ag69/Youshallfearme2/9c16d016-f80b-457f-929f-281c69c4e112_zpsa695426d.jpg)
Once you find your image then your screen should look more or less like this. On the right hand side gives you coding so this certain image can be viewable on other websites
(http://i1299.photobucket.com/albums/ag69/Youshallfearme2/19fb9805-b00e-44f0-bd5c-600a6577b899_zps5dda90a5.jpg)
from there all you need to do is copy this coding only in the IMG section found on your right hand side of photobucket. After that you need to shuffle back to Feral Heart and go into your profile and click on Forum Profile Edit
One you got your picture really just place it in your comment box on a trend and that all ya do.