I have problem with responsive layout

for example here

http://makemoneyrelax.com/fuji-restaurant-chain-bangkok-thailand

when you watch the site in 1000 px layout (normal layour) the images of cck fields are too big, how to scale them down?

Somebody mentioned to use width 100% and height auto in css but it does not work that well.

i think i will switch to 960 grid only and not use 1200 or narrow and mobile because of the issues with images, i want to have big images displayed, any solution for this?