A size for ants, jokes aside though is this some kind of size for phones or something? 512 x 512 is unusual in my humble opinion. The heavily pixelated first page stands out like a cold sore as well and could really need a replacement.

Base +22, Jadia +7, Ultimax-Bonk +3

Yes, it's for mobile devices.
Product homepage: http://renaireplay.bushimo.jp/
Illustrated by: Kamo (加茂) - http://www.doujinshi.org/browse/author/278/Kamo/

Base +9