Thumbnail size of Single-Property Page

Over the mobile version single-property page, found that 2 rows of photos are of same size. Understand in web version the bottom row photos are thumbnail preview. While, it can’t be identifield clearly under mobile version.

See as attached…
https://goo.gl/Bojc6x

Wonder if there’re any setting I can fix it to display more thumbnail in single mobile screen? Thx!