Video Thumbnails Dolphin 7

I have used Dolphin 6 in the past and was able to change the thumbnails on videos that were uploaded. With Dolphin 7 I do not see an option on changing the thumbnails. Most of the videos are a black thumbnail. how can the thumbnails be changed? Please help. Thanks

http://www.boonex.com/unity/forums/topic/Flash-Video-Quality-Mod-.htm

go tot the  bottom of the page and you  will see it ....

Using Dolphin 6.1.6 and can not find the function grabImages in the path /flash/modules/video/inc/functions.inc.php referred to in

http://www.boonex.com/unity/forums/topic/Flash-Video-Quality-Mod-.htm.

Would very much appreciate a 6.1.6 solution for changing the thumb pic from the beginning of the video so that the thumbnail isn't black.

Thanks in advance for your help.