Tony's method is the best method I have come across.
There is a feature in which you might be interested that you can use in addition to Tony's method. On my screen there's a button that's hidden and I have to resize the preview monitor until the button is revealed. The pop-up tip for that button says "Manage your media libraries." On the default screen layout, the button is just to the left of the preview monitor and above the media room. You can import, export, and empty libraries.
When you import a library, you can merge them with the current library. Then you can export that whole bunch to a new library file, for example. If there's a way to make a library a default library, I don't know what it is. At least you can import different library configurations in one shot.
You can also add images to the SampleClips subfolder where you installed PowerDirector. They will be read in each time you start a new project if you have the option in preferences turned on to read the sample clips. Note that you can't add your own folders in the SampleClips subfolder, just single files. I know that JPEG files work. Other media types may work, but I haven't tried them.
Gateway DX4380, AMD A8-5500 Quad Core 3.2GHz with ATI Radeon HD 7560D; 16GB RAM; 1 TB SATA 7200 RPM; Windows 8 Pro 64-bit; PDR11, PDVD12.