currently the image size brackets are
lowres (500×500 or smaller)
no resolution tag (larger than 500x500 and smaller than 1600x1200)
highres (at least 1600×1200)
absurdres (at least 3200×2400)
incredibly absurdres (any dimension over 10000)
since time, tech and perseption have moved on quite a bit since those brackets where made, with 500x500 practically being small avatar size these days,
i suggest changing them to :
lowres (1200×1000 or smaller)
----almost everything new in this category is going to be low res advertising samples of paid for work or near historical items from the dawn of booru
no resolution tag (larger than 1200x1000 and smaller than 1920x1200)
highres (at least 1920×1200)
-----its been 2 decades since 1600x anything was considered high res 1920x is at least the first common hd with 720 passing like the windows vista of hd resolutions
4khd (at least 4000×2400)
----- rounded off to a clear number close to 4khd
8k-hd (at least 8000×4000)
absurdres (any hd image with otherwise rediculous proportions like full cast banners or dakimura)
replacing the "absurdres" language with 4k-hd, 8k-hd 12k-hd would future proof the tags and make them more objective.
since i suspect 8k images are going to end up as standard in the next 3 or 4 years, making the current tags a little silly.