According on Yande re, the artists name is Matsuzaki Izumi or Izumi Matsuzaki (In Kanji "まつざきいずみ"), though can't seem to find anything about the artist here or either anywhere, anyone knows?
does danbooru have a strict tagging guideline for anime poster magazine scans? because honestly I'm not sure
Danbooru is slightly lax with official_art posts in regards to artists including these kinds of magazine scans, though the majority of scans (around 85%) have an artist tag anyway. We can tag it here since we know who it is, so I'll make a tag for her.