sorry tainted heart, i don't know what country you are from, but i am English, and anytime i have encountered the word "sick" would be in that i may have made a joke, and then a mate may reply "that is sick" which just means that the thought of whatever i said grossed them out a bit, like maybe it gave them an imaginary visual they didn't quite like(feel comfortable with) it isn't a harsh insult, it would just mean it was a bad joke!! maybe you could contact the person in a friendly manner and just ask what they mean. e.g did your image actually offend them, or was it just they found it a distastefull joke, if it upsets you though, i think you should ask a mod to remove the comments.