adjust image size mobile version (css, bootstrap)

for website
https://www.stahlcarport.at/immobilienverwaltung.xhtml

there are 3 blocks
the centered in mobile version (4540 Bad Hall) has full image size

i also need the first (5030 Bad Hofgastein) and the last one (4600 Thalheim) with same image size as the centerd one.

i want leart css so i cannot give server access.
just send the code i need to change in message box