Your attorney will want to know if the Getty Images are images made for Getty Images, e.g., does Getty Images own the Copyright to the Getty Images? Your question either assumes that Getty Images is not the Copyright owner of the images or the use of the word "troll" has come to mean that an entity which protects it's property is acting improperly. Your Intellectual Property attorney will have several questions.
My comments have been made without discussion. An attorney client relationship has not been established. There may be conflicts which prohibit my providing you with specific legal guidance. Any contact with you beyond these few general words will start with a disclosure of opposing parties so that a conflict check can be made. You should discuss with an attorney.
Traditionally, you would either file a class action on behalf of all similarly situated plaintiffs, or you would file it as a mass tort action naming all the hundreds of plaintiffs individually. Your first step would be to locate a competent local business litigation attorney and/or class action plaintiffs' lawyer, and see what they have to say during a personal consultation. I believe Kreindler & Kreindler filed a class action late last year against Getty on behalf of professional photographers.
Your premise is wrong. Getty Images is either the copyright owner or the exclusive licensee of the copyright owner for all the photographs in its collection. As such it certainly has the right to enforce its copyrights against all infringers. In fact, it has the right to sue them without first contacting them via a cease and desist letter and offer to settle. Infringers are LUCKY that they're contacted first instead of being served with a federal complaint for infringement. Call those settlement demand letters "exortion" if that makes you feel better but you are flatly -- and arrogantly -- wrong.
The above response is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.