Changing Size of Catalog Photos?

I am using the theme Mystile, I removed the left side bar and attempted to increase the width of the shop paged however could not solve the problem. I ended up going to sleep waking up the next day and finding out that the size of the category pics was too big, it is only giving me columns of 1 and 2 on my shop and home pages. I changed the code to }
ul.products li.product img {
width: 45%!important;
height: auto;
padding: .53em;
display: block;
-webkit-box-sizing: border-box;
/* Safari/Chrome, other WebKit */
-moz-box-sizing: border-box;
/* Firefox, other Gecko */
box-sizing: border-box;
/* Opera/IE 8+ */
border: 1px solid #e8e4e3;
background: #fff;
margin: 0 auto 1em;
}
from
}
ul.products li.product img {
width: 100%;
height: auto;
padding: .53em;
display: block;
-webkit-box-sizing: border-box;
/* Safari/Chrome, other WebKit */
-moz-box-sizing: border-box;
/* Firefox, other Gecko */
box-sizing: border-box;
/* Opera/IE 8+ */
border: 1px solid #e8e4e3;
background: #fff;
margin: 0 auto 1em;
}
however still no luck, out of desperation I then deleted the theme and reinstalled it, still the same problem.
Can anybody explain how to fix this problem? Thanks all.