The context is: "The magical girl gets doxxed by the bad guys before she has a chance to transform/henshin".
The artist's twitter has long gone, and reverse search turned out nothing. This is the closest to source I could get.
Updated
Well, well...
This is what Sapphire Star-chan looks like before transformationshe looks cute... though kinda mousyNo... I'm notplease... please don'tHey, why don't you transform right here? There are normal people around, though