@zach-mx There is an image component for anything that is static (say for example your background). You really only need to use filmstrips for dynamic components such as sliders and buttons. Otherwise you more or less have the process right.
It is usually recommended to export your images 2X larger than your UI and scale them down (in order to deal with different displays). If you can use Hise LAF/Painit Routine for anything, it is usually better than using a filmstrip or image. Keep in mind that the z-level works bottom up, so the last component you add to your UI will be "above" the other components. You can rearrange this in the Component List of the HISE interface.