Go to the library and get the book "Writer's Market" That will give you the guidelines for submitting artwork (and writing) to specific magazines. Else send them a query letter (usually not an email) to the art department asking for submission guidelines.

Randomly sending in artwork will usually get trashed before it is even open. Most magazines receive hundreds if not thousands of submissions and if you don't go through proper channels then you would get through at all. Even if the submission has the wrong name on it - it could get trashed.

Watch out for "editorial submissions" as you may not get paid for their use. Read the terms clearly for each magazine.

Note: writer's market deluxe edition has a year subscription to their updated database and community.

Jade