I believe these photos were taken for the April issue of the Japanese magazine, Josei Jishin [女性自身]. Josei Jishin means ‘Women themselves/herself”. According to yystudio’s blog, they are located in Nonhyeon-dong, Gangnam and specialize in wedding, profile, and family photos. I noticed that they also had many photos of other celebrities and drama photo shoots as well. Please refer to my May 2nd post on this magazine. You can also type in the tags “Japan” and “Josei Jishin”.
Original link to Seung Gi’s photos on their blog: yystudio