Currently we only have Realistic and photorealistic. With the following wikis:
Realistic
Art with a more realistic approach to its anatomy, proportion, lighting and so on.
Use photorealistic for posts so realistic they could be mistaken for photographs.
photorealistic
Posts so realistic that they could be mistaken for photographs except upon close inspection.
If these were used correctly it would lead to everything from "more realistic" to "incredibly realistic but not photo like" getting in the same category. Instead what we get is that exact problem combined with things that cannot be be mistaken for a photo getting tagged under photorealistic presumably to separate them from the quality found in realistic such as post #7258069 post #7215833 which should be in realistic or could only be mistaken for photo from the thumbnail post #6758023 post #7139579 (I am going to assume "upon close inspection" doesn't just mean "click on it")
Having three "tiers" instead of two allows for realistic to be for posts like the above and photorealistic to be used for its actual purpose.
Just going through realistic pokemon leads to there being no difference between things like post #625045 post #3344899
This is a large change and I will be away for a few days so I will be leave you guys to maybe try and think of a name. In the meantime here are some examples of what requirements for the different "tiers" could be.
Pseudorealistic: post #3344899, post #1199784
Realistic: post #625045 post #7258069 post #7215833 post #6586213 post #6758023
Photorealistic: post #6692616 post #153488 post #6221469