An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating an art. The common usage in both everyday speech and academic discourse is a practitioner in the visual arts only. The term is often used in the entertainment business, especially in a business context, for musicians and other performers (less often for actors).
If the person who is posting such material claims falsely that the material is his material, it will a lie and a sinful act.
If he does not claim any wrong claim but he is just posting a material for the benefit of people, with out harming any one, then it is allowed to spread useful knowledge which helps people and does not cause harm to any one.
Yes it is allowed to become a comic artist as far as it does not insult or degrade others or promote falsehood.
Comic art is like any other fine art which must promote noble values, not otherwise.
Unfortunately , we see now a days many artists promote wrong ideas and wrong practices under different slogans like freedom of speech or personal sexual freedom causing misleading lay people and making them suffer, instead of guiding them to the real values which leads to successful life.
There would be no problem with drawing or painting. Such an art is a valued talent and indeed must be appreciated.
A problem would arise if:
1. You are making full sculptures of humans or animals. If it is something that has a "soul", then it is not permitted to make a sculpture of it.
2. It is a promoting of anything that represents any deviancy, immorality, or anything un-Islamic.
And Allah knows best.