Personalized thumbnail for community contracts

Does anyone know how to can change the thumbnail of a contract you’ve made yourself? I saw an example of this in a contract called The Vomitting Man in Chongqing (PS4); the contract ID is 2-30-4115814-52 by blinkybop23, I’m case you guys wanna see what I mean.

Here’s a photo of the briefing and the contract thumbnail/photo:

Oh, I haven’t done the escalations for Chongqing. Thanks you. But yeah, I really wish they let you change the photos to make the contracts more unique.