Ok...bad news first: United States law no longer requires the use of a copyright notice. Further, a copyright is created as soon as the image, song, literary work, calendar or other original works of authorship is fixed in a tangible medium of expression. Unfortunately for you, Getty Images has every legal right to demand payment for use of their image, regardless of what you did or did not know.
Potential good news: You did the right thing by removing the image from your site. I have no experience with Getty Images, however, your gesture of submission may be sufficient for them to call off the hounds. Be sure to let them know that you acted innocently, have now been educated and know the error of your ways, and will be sure to educate others about Getty Image's property rights. If that doesn't work, you may be able to negotiate a lesser fee based on the limited time of use.
Lesson learned: In the words of my mother: "If it doesn't belong to you, don't touch it unless you have the money to buy it". How true.
Answered on Oct 27th, 2011 at 1:39 PM