Setting TileMill Shield Size?

Question

I'm trying to set my shields on the map which contain only image (I don't want any text at all - only img). I can't change size of img. I tried markers too but I can't get them orientated like shields (no rotation, shield on the line).

How can I achieve that?

As you can see icons are way too big but I don't want to change size of files.

    #rowerowe {
    [colour='red']{
    shield-file:  url("D:\Leaflet\img\red.png");

    shield-face-name:"Arial Bold";
    shield-size:16;
    shield-fill: black;
    shield-line-spacing:5;
    shield-min-distance:1;
    shield-allow-overlap:false;
    shield-placement:line;
    shield-dx:150;
    shield-spacing:450;
    }
 }

Here's the same with markers, I can change size but can't change orientation to "top".

#rowerowe {
    [colour='red']{
    marker-file:  url("D:\Leaflet\img\red.png");
    marker-width:24;
    marker-height:24;
    marker-placement:line;
    marker-spacing: 200;

    }
 }