QImageReader guess a wrong format for tga image

QImageReader reader(QLatin1String("test-flag.tga"));
reader.setDecideFormatFromContent(true);
QString format = reader.format();

qDebug() << "Image format: " << format;

When the QImageReader setDecideFormatFromContent(true), and loaded a tga image, the format may returns "ico".

It seems that the ico plugins miss canRead the tga image, since the ico format handler is try before tag format handler.

Please notice that the tga image was taken from qtimageformats/tests/shared/images/tga/test-flag.tga.