I think it depends on what the distrubing thoughs and images are. Disturbing thoughts and images could mean different things to different people.
And there are degrees to them too I suppose.
And then there is the question of, do they pop in and pop out, or do the pop in and stay there for a long time?
Also, how distresing are they?
And do you feel any compulsions along with the thoughts. Do you feel pressured to act on them? Do you act on them.
Or do you have to do certain actions or say certain words to get the thoughts to go away.
I think all of that would help determine if it is OCD or another disorder.