Encode and Inline an Image for faster loading in PHP

function encode_image($filename)
{
    $contents = file_get_contents($filename);
    $base64 = base64_encode($contents);
    $imagetype = exif_imagetype($filename);
    $mime = image_type_to_mime_type($imagetype);
    return "data:$mime;base64,$base64";
}

echo "<img src='".encodeimg("images/userimage.jpg")."'/>";