img.Save(file, quality)
===== Sample =====
function OnStart()
{
lay = app.CreateLayout( "linear", "VCenter,FillXY" );
img = app.CreateImage( "/Sys/Img/Droid2.png" );
img.SetLineWidth( 2 );
img.DrawLine( 0,0,1,1 );
lay.AddChild( img );
app.AddLayout( lay );
// High quality jpeg
img.Save( "/sdcard/test95.jpg",95 );
// Low quality jpeg
img.Save( "/sdcard/test05.jpg",5 );
// png ignores quality
img.Save( "/sdcard/test.png" );
}