My post rule34.xxx/index.php?page=post&s=view&id=9989379
has 2492x3000 (Original size which came directly from twitter).

Yet right next to it is rule34.xxx/index.php?page=post&s=view&id=9989409 which is 3404x4096 (Much higher than the original)

What do they say about reuploads/dupes that are much higher than the original image even though they are the exact same size as the source?

Simple, their not from the same source. A trick people try to do is post the pay walled version and link in a way that makes their upload look valid.

Alright, thanks.

I'm just asking because i don't want my post to be taken down for being a "inferior duplicate".

Inferior duplicate is like the sample JPEG pics you get from Google like are like 700x1000 with jpeg fragments and bleeding colors