You should occasionally (especially on the base game pages) come across an image with a dotted border, like so:
This indicates an item that has been converted before but is no longer available from its creator/wherever it was originally uploaded. Clicking it will take you to the new Orphaned Conversions
page, where I've compiled all the affected downloads by creator. When possible, I've noted alternate places to download things.
The purpose of this is to make it clear to downloaders when an object might not be available anymore and to convertors when an object might need to be reconverted.
Right now the affected items are from nengi65 (all or mostly all archived by leefish), littlecat (shared by myself), and
The Ninth Wave's Sapphire Sims uploads