Metadata block requirements

Hello,

I have recently found a number of FLAC files that have a PICTURE block 
as the first metadata block in the file.  From the format documentation, 
it mentions that the STREAMINFO block must be present as the first 
block.  I'm guessing that someone somewhere is not playing nicely with 
the format, but I just wanted to confirm that this is incorrect so that 
I can fix the files if they are bad.

Thanks,
Ron