procedure GetDPIImageFile(fn:string;var dpix,dpiy:integer);
var
  img:Timageenview;
  ff: TIOFileType;
begin
  img:=Timageenview.create(nil);
  try
    ff := FindFileFormat( fn, false );
    img.IO.ParamsFromFile( fn, ff );

    dpix:=img.io.params.dpix;
    dpiy:=img.io.params.dpiy;
  finally
    img.free;
  end;
end;