The original illustration is an in-game cg, but I could not find any datamined image. We need a dataminer.

ankakechahan said in comment #2583258:

The original illustration is an in-game cg, but I could not find any datamined image. We need a dataminer.

For anyone wanting to take this on, this is a DMM/FANZA browser game, which means you'll need a DMM/FANZA account and a Japanese VPN (using FANZA will let you access the R18 content as well).

The image will likely be added to https://muvluv-girls-garden.wikiru.jp/ soon, but the images on there seem compressed and I don't know if the raw assets have the same compression.