Her expression looks gloomy because she's young! It's probably because she's hesitantly complying with the photographer's requests! Such a beautiful girl doing something like this! Isn't this what Girls Delta is all about?
It's a shame that the photo used on the page listing her platinum-level works gives off the vibe of "the madam of a bar in a multi-tenant building in Akabane"... but she's a very cute woman with a wonderfully lovely smile. What's impressive is that the photo is full of "dynamism" (something completely absent in her recent works). I hope to see more exciting works like this in her next projects!