This is not a dupe.
This one has fewer notes than 40081 and was also uploaded way before post:40081. You can still view it through yusa.imouto.org/image/e13bdc4c70d0389a6657c4e162a38483.jpg.
Actually, this should be the parent post of 40081, IMO.

I know mods are doing their best to make this site clean and nice, but mods should really be careful when deleting posts.

That's a minor difference.

Unless I'm mistaken it was also deleted 3 years ago...

Yes, there is only minor difference, but if you compare this pair with post #121829 and post #181038(uploaded only 3 month ago), the difference is not minor.

What I really concern is that there is no consistent rules on what post should be deleted. A most recent example, is post #189549, which was uploaded only 2 days ago, with a resolution of 1280x1024. It got deleted because of low-res while post #157621( 10 month ago, 1200x889) survives.

If you want to improve imouto org, as admin2 and mods mentioned in forum, do make some consistent rules and do stick to it.

Don't make your users think that their favorite posts will get deleted one day randomly without a valid reason.

(Edited your post links - Radio)

One could say we are consistently... subjective.
Check out forum #13582 for the reason behind recent low-res deletions.

MoeJoe said:
Yes, there is only minor difference, but if you compare this pair with post #121829 and post #181038(uploaded only 3 month ago), the difference is not minor.

I can't understand why you are comparing those images? One has colour issues, is a JPG but is a pool member. The other appears colour correct, is a PNG, but has aliaising, and is lower-resolution.

van said:
One could say we are consistently... objective.
Check out forum #13582 for the reason behind recent low-res deletions.

Fixed that for you.

I understand why post #189549 was deleted. It was in the mod queue and hadn't been approved. The deletion reason, perhaps, could have been a little clearer.