This picture is a part of the ARG released for the 6th anniversary of Magia Record: Mahou Shoujo Madoka Magica Gaiden. Those pictures are currently share-able on Twitter using a button on the main anniversary page: https://6th.anniv.magireco.com , and contain clues for unlocking the secret hint for this year's anniversary unit (it's Akuma Homura).

Those images were released for every Magia Record original character which has a unit, with an exception for characters that are dead, and characters that were introduced in the anime (Kuroe and Kuro).

I am not sure if I'm going to be uploading all of these, given those are just everyone's card arts, but for those interested - here's a Google Drive folder with all those images: https://drive.google.com/drive/folders/10hMibe1-sHSfXjdX4A-dtCyNCyJv-VSh