I've read on another thread:
WP-SimpleViewer comes bundled with SimpleViewer-Standard (the free version) which does not support Pro configuration options. When you upgrade the plugin, it will use the latest version of SimpleViewer-Standard.
Upgrade your version of WP-SimpleViewer to SimpleViewer-Pro (by following the instructions here) and your galleries will use the Pro configuration options which are still stored in your gallery XML files.
The latest version of WP-SimpleViewer (v126.96.36.199) includes new functionality whereby a Pro 'svcore' folder will not be overwritten when the plugin is automatically updated so the next time you update the plugin, you will not need to manually upgrade to Pro.
I have tried thrice to install version 188.8.131.52 of the WP-SimpleViewer plugin, but upon installation, all my galleries revert to having the SimpleViewer logo in the bottom right corner, like the free version. Each time I have to restore the svcore from the Pro folder on my computer.
Is this "functionality" you speak of supposed to apply to future versions not inclusive of this one, or is it supposed to apply to this version as well?