var img = document.getElementById('image'); 
var height_orig = img.offsetWidth;
var width_orig = img.offsetHeight;
ratio = width_orig / height_orig;
if( (width_orig < 480) && (height_orig < 360)) {
thumb_new_height = height_orig;
thumb_new_width = width_orig;
if(ratio==1) {thumb_new_height = 75; } else {thumb_new_height = 100; }
 thumb_new_width = 75;

} else {
if( width_orig > height_orig) {


 thumb_new_width = 100;
 thumb_new_height = 100/ratio;
}else if( height_orig > width_orig) {


 thumb_new_height = 100;
 thumb_new_width = 100*ratio;

}else if( height_orig == width_orig) {

thumb_new_height = 100;
 thumb_new_width = 100;
}
}