Whenever a higher resolution version of an old post usurps the old one, all of the original's votes are lost to the aether, as are its comments.
Every image page of an updated post is affected.
The votes should transfer as the favorites already do, and the old comments should be readily accessible in some way, possibly through an "Old comments" section separate from any new comments to avoid confusion.
Instead, everything is just lost, nuking popular posts from the front pages of order:score searches.
This occurs every time a post is updated.
Honestly, keeping the votes and comments would be another incentive for people to upload higher res versions, and just imagine if this happened to a historic post like the cheese grater, or the earliest surviving post.
Updated by Siral Exan