Are your own personal photos and artwork automatically copyrighted upon creation even though you may not have formally gone through the copyright process?

I heard they were.
The reason I’m asking is because unfortunately I have found a pic of myself that I took floating on this site called jerk dot com and I’m not too happy it landed on there. Not sure how they got a hold of that picture in the first place. I have never heard of nor visited the site before.The picture isn’t anything racy or bad, just a normal shot one would take.

So would they be infringing on my copyright because they posted it without my permission or knowledge?