Concerning your concerns: I'm pretty sure direct linking is the polite term for hotlinking, their permission is implied since they provide the info for you in a variety of formats. Plus the site was originally created asan image host for reddit. I googled a bit and I guess they are ok with use on forums but prefer you use the embed unit for nsfw and albums. Kinda mixed results for use on non-commercial blogs which their FAQ doesn't really settle for me.