if(opts.panel_scale=='nocrop') {
                    panel_img_scale[i] = Math.min(opts.panel_height/img_h[i],opts.panel_width/img_w[i]);
                } else {
                    panel_img_scale[i] = Math.max(opts.panel_height/img_h[i],opts.panel_width/img_w[i]);
                }