I'm looking to teach learners about network firewalls. The worksheet mentions that 'All images should be checked to make sure that they don’t have more than 40% of the image with the following RGB values:
○	197, 140, 133
○	236, 188, 180
○	209, 163, 164
○	161, 102, 94
○	80, 51, 53
○	89, 47, 42'.
Are you able to explain why a network might block requests to images with more than 40% of these RGB values?