Yes, you are free to advertise your work here as long as it's legit. I have seen some users that advertises different skills and services on the service board and you can also post your art works there but you have to undergo the few process that have been outlined on the first comment, because that's only when you can be able to post visible images or you can just post the links of the art works and continue making post in other sections and once your activities is up to 30, you will become a junior member rank and all your images will begin to display.