Prevent image upscaling on photosets

.portfolio_single.is_photo .post_media img, .portfolio_single.is_photoset .post_media img { display: block; width: auto; height: auto; max-width: 100%; margin: 0 auto; }
.photo_slideshow .photoset_photo, .portfolio_single.is_photo .post_media .photo_single { text-align: center; }
.photo_slideshow .photoset_photo a, .portfolio_single.is_photo .post_media .photo_single a { display: inline-block; }