Copyright gives you exclusive rights to an item, including the right to reproduce and sell it, and to make derivative works from it (eg paintings adapted from the original) as well as the right to display the copyrighted work public-ally.
There is no such thing as international copyright that will protect your rights in every country. Each has their own laws and agreements with other nations regarding copyright. The two main international copyright conventions are the Berne Convention and the Universal Copyright Convention. The information given in this copyright FAQ for artists is based on US copyright law, but the principles are similar in other countries.
Go to Full Artist's Copyright FAQ.
Disclaimer: The information given here is based on US copyright law and is given for guidance only; you're advised to consult a copyright lawyer on copyright issues.