Does that mean I own the design and am still free to publish my work elsewhere ?

Yes, your design belongs to you and you alone. All we do is help you print them on a shirt and sell them hassle-free. You are free to publish your work on any other platform, and we encourage you to link your profile from Teetalk.ph so people will know they can get it on a shirt. Feel free to update your artist profile for people to see more details about you.