Where do you upload PROOF pics for the Blackmail Feature?

Ive been testing the blackmail feature as I think the idea is great. 1st I did a trail where I left the task. Then I wanted to try 1 where I submitted something that would fail... only to find out I cant figure out where to submit a pic in the 1st place. Where is it?

You can try submitting via the "rounds" section within the self-training task card. However, it may sometimes take a while for the submission to appear.