Gallery v1.5.3: Performance Improvments & Daily Maintenance

The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL: [FRONT END ACCESS]
Gallery version: v1.5.3
Apache version: Linux
PHP version: 5.2.6 on an Apache Server
Graphics Toolkit:
Operating system: OSX Tiger
Web browser/version: Mozilla / SeaMonkey

I've been using Gallery v1.5.3 for some years now and from the start it's worked just great. However, over time I've noticed performance declines related to the speed which a page loads. Is there a maintenance check I've been neglecting? Is there something I can do to improve the speed performance? This site use to load the images much quicker. Perhaps I need to clear cache or something?

Please direct me on how I can better maintenance Gallery 1
Your assistance is greatly appreciated!

This gallery is modified and bridged w/ Mambo.
You may access the Gallery directly
[ CLICK HERE ]

Thanks!
Smitty