I previously asked a question on whether chicken contains suet and the answers was no. however if you look at his picure the tissue highlighted in red looks like suet. If not suet, what is this and how is it different from suet?
"Suet" is beef fat, especially from around the cow's kidneys. By definition, a chicken cannot contain suet, unless it's recently eaten some beef.
The bits you've circled are fat deposits, though, like suet. In a butchered chicken, it's easiest to find similar fatty deposits on the thighs, back, and tail. The breast and wings have comparatively little.
I don't think there is a specific name for it other than "chicken fat", but I am not a butcher. Depending on where it comes from on the animal, it is either intramuscular (between the muscles) or subcutaneous (between the skin and flesh).
The fat used in suet is more dense with a smoke point of 400F (204C) and contains around 45% saturated fat. Chicken fat is softer and more malleable, contains 33% saturated fat and has a lower smoke point of 325F (162C).
In chicken, the thighs and the parsons nose are good sources, as well between the breast, back and the skin.