[Plugin: Flickr Gallery] Invalid XHTML

Hi, I am trying to get my page to be Valid XHTML in line with the W3C. I have the flickr gallery plugin installed in my wordpress site and it is throwing up errors in my code for this. The specific error is that in the header of my site the flickr gallery css files are being linked, but media=” is blank, where as to be valid xhtml it should be media=’all’>. I have looked through the php file but cannot see the part of the code which would add “all” into the media type instead of blank. Could you help me with this please. Thank You.

<link rel='stylesheet' id='flickr-gallery-css' href='https://test.artsoflife.org/wp-content/plugins/flickr-gallery/flickr-gallery.css?ver=1.3.1' type='text/css' media='' />

<link rel='stylesheet' id='fg-jquery-ui-css' href='https://test.artsoflife.org/wp-content/plugins/flickr-gallery/tab-theme/jquery-ui-1.7.3.css?ver=1.7.3' type='text/css' media='' />

<link rel='stylesheet' id='jquery-flightbox-css' href='https://test.artsoflife.org/wp-content/plugins/flickr-gallery/flightbox/jquery.flightbox.css?ver=1.3.1' type='text/css' media='' />