I am very much a newbie.  I updated Joomla from 1.5.25 to 2.5  I think I have almost everything working but I think the tags for the galleries "may" have changed??  Anway, they are not working.  If you look at:
netwit.info/index.php/gnr/2010/photo-gallery 
or,  netwit.info/index.php/gnr/2009/gnr2009
you will see the tag does not work.  It may be the size of the photos are too large for the window??  Any help is greatly appreciated. Please let me know what additional information you need.
>> Dennis  :)

First of all I cannot see Simple Image Gallery plugin in your source code... Did you enable it?
Secondly, these are captions:
0|100_0568.jpg|PreRally NetWIT Pizza Party held on NetWIT row | 2009
and are only compatible for Simple Image Gallery PRO plugin not the free version you said you have.
However, even if you had SIG PRO these captions wouldn't work cause are in the wrong place and are written in a wrong way.

Katia,  Thank you for your quick response.  I appreciate your patience with me.  I uploaded the Simple Image Gallery plugin and, Yes, I enabled it.  It shows on the plug-in as enabled.  I am the new webmaster for this site.  Is it possible that it was operating in Joomla 1.5.25 with Simple Image Gallery PRO and when I migrated I lost it?  I have lost the backend of my 1.5.25 version so I'm not sure how to check this???  I have the front end on my pc.  I am more than willing to buy the PRO version but I guess they still would not work if they are in the wrong place and written in the wrong way.  You said they are only compatible for the PRO?  Help me understand why?  Is it the type of files, or something?  I'm just trying to figure out how to fix the original website on 2.5.  Thanks in advance for any advice.
>> Dennis

Simple Image Gallery  cannot provide captions to the images.
SIG PRO can!