Favicon Image Sizes
Tests that the favicon contains 16x16 and 32x32 icons.
According to RealFaviconGenerator, the favicon.ico file is only used by IE (if you configure your meta tags correctly), and the only sizes it uses are 32x32 and 16x16. Therefore, this test will produce a warning if either the 32x32 or 16x16 sizes are missing. You are welcome to include additional sizes, but we recommend against it because it will unnecessarily increase the filesize and impact performance.