birddog
The problem is the url you are using points at whatever were the last additions to your gallery. While they may be correct at the time of posting the message these are dynamic links. Best to go to the gallery then navigate to the image and use the resultant link as the link for posting as this will be a static link.
As an example here is one of your Dobroyd head links obtained this way.
http://www.pixspot.com/displayimage.php?album=53&pos=0
The giveaway is that in the links that don't work it has album=lastup rather than album=xx where xx is a number
Hope this makes sense