If you are using Getty images then you should follow their instructions to the letter.
They are well known for chasing / suing websites that are using their content in the incorrect manner – usually chasing a minimum price of around $2K per image.
They also use robots to look for similar matches or pictures on the web, and this can produce false positives, but it does not stop them from acting in a very law suit happy manner. We ran into an issue with affiliate banners we were displaying that contained portions of some of their images, and it took quite some effort and discussion for Getty to accept that the banners were legitimate 3rd party use of banners created by a legal licensee.
If you require clarification about using a different approach to display images then you should go directly to Getty Images, and keep a copy of all correspondence safe. Getting advice here without OK from Getty Images will not be much help.