After server upgrade the plugin has stopped displaying thumbnails, but still displays pop ups. I have checked the Permissions and they are set at 755 or 775. 
As anyone else experienced this and is there a quick fix for this issue?

Thanks,
Desw
???

Could you provide a link to your site?

Since upgrading my Joomla installation to 1.5.23 the thumbnails for SIG Pro do not work. I have uninstalled and reinstalled the plugin, deleted the galley images and even set up a new installation to test the plugin in a completely new installation, to no success.

I have scoured the forums and run Google searches and found no useful info, although this seems to have been a common problem with other users prior to the latest core Joomla upgrade. The solutions presented don't seem to jibe with my installed files, some of the fixes reported included changing the permissions on a "showthumbs.php" file but I can't find a file named as such.

The URL for the affected gallery is:
www.santafedigitalimage.com/index.php/Photography/photography-portfolio.html


Thanks,
Robert

I found this post WAY back in the forums, and it applied to my site, hosted on Rochen Host:

Re: Another Thumbnail Problem...
« Reply #2 on: February 15, 2011, 04:04:15 AM »
Quote
To update anyone interested:

Both the sites listed above in the initial note had the exact same .htaccess file. Through a little research, I found the following lines:

## Disallow front-end access for certain Joomla! system directories
RewriteRule ^(includes/js/.*)$ - [L]
RewriteRule ^(cache|includes|language|libraries|logs|tmp)/.*$ index.php [F,L]

I took the "cache" from the second RewriteRule so that it appears:
RewriteRule ^(includes|language|libraries|logs|tmp)/.*$ index.php [F,L]

I've done this ONLY on the www.stephenseal.com site and everything APPEARS to working well.

CAN ANYONE tell me if I've opened up a crucial security problem by removing cache from this line so that SIG PRO can work?

I know NOTHING about the .htaccess file so I'm shooting blindly here....

Regards

To sum this up, the .htaccess file is preventing the Simple Image Gallery Pro (working from the front end of the site) from accessing the thumbnails which are stored in the cache folder. This setting is changed from the default .htaccess file if you use Rochen's Joomla Utilities in the CPanel and use the security settings updater. I had utilized the Security Tweaks under the Security Tools after using the Update Joomla Core to update to 1.5.23.

This SOLVED my issue with the thumbnails, and I would suggest that anyone having problems with thumbnail display investigate this avenue first.

Robert

What you shoud do is fix your cache permissions in order to be writtable as it is said in the documentation REQUIREMENTS paragraph.