If you use width or height tags to resize images, In IE6 and 7 will not resizing images properly. This little css tip will make IE happy in resizing..
-ms-interpolation-mode: bicubic;
img {
max-width: 100%;
width: auto\9;
height: auto;
vertical-align: middle;
border: 0;
-ms-interpolation-mode: bicubic;
}