Thumbnail is NOT as "Responsive"

/ow_themes/simplicity/mobile/base.css  -  Line 3384
/ow_static/themes/simplicity/mobile/base.css  -  Line 3384

Should be as follows:
.owm_index_photo_item a {
    background-size: cover;
    display: inline-block;
}


Also at Photos Page (www.yoursite/photo) the thumbnails should include a background position of "center center"...

/ow_themes/simplicity/mobile/base.css  -  Line 3006
/ow_static/themes/simplicity/mobile/base.css  -  Line 3006

Should be as follows:

.owm_photo_list_item a {

    background-position: center center;

    background-size: cover;

    border: 1px solid #ecf1f6;

    display: inline-block;

    vertical-align: top;

    width: 100%;

}