C# read GFIE document as Image

/**
 * Read a GFIE (Greenfish Icon Editor Pro) document and draws it to a image
 * Currently supports:
 * - Multiple Layers
 * - Layer Visibility
 * Currently doesn't supports:
 * - Pages
 * - Layer Opacity and Blend Mode
 *
 * Depedencies
 *
 * GFIEFormat class from Greenfish Image Converter
*/
Bitmap gfieToImg(string file,int page){
    GfieDocument doc = new GfieDocument();
    doc.LoadAsGfie(file);
    GfieDocument.LayerCollection ls = doc.Pages[page].Layers;
    Bitmap bmp=new Bitmap(ls.Width,ls.Height);
    Graphics g=Graphics.FromImage(bmp);
    for(int i=(ls.Layers.Count-1);i>=0;i--){
        GfieDocument.Layer ly=ls.Layers[i];
        if(ly.Visible&&ly.Opacity>127){
            g.DrawImageUnscaled(ly.Image.Image,0,0);
        }
    }
    g.Flush();
    return bmp;
}