Changing width of header and slider messes up my image gallery

I need only my header and featured image slider to be 770px, but when I use .woocommerce img, .woocommerce img-page{ max-width: 770px; } it makes the gallery that I have on my homepage in the featured content section go all out of whack. I've tried to exclude the gallery from the width restrictions, but then it excludes both the image slider and header from the restriction as well. Please please please help! My site is: www.sneaksthatspeak.com