I do not see how standalone versus a forum integration would matter with that options here is 8.23 on my site with my
vb integration turned off using the standalone style so thats not your issue
A community photo gallery - ReefTalk Gallery
Is the recent thumbnail block set to be turned on in your options. Have you ran any required upgrades and your sure your using all the proper files depending on what version you updated from.
You can send me more info to look at your site if your sure all options are set right etc