It is important to understand the limited role of the dynamic colors. These represent the colors used to display the user interface elements on which your icon appears. If your icon appears in File Manager, File Manager determines what the background color is. If the user changes the color palette in Style Manager, the colors in the user interface change to match, and the background color the icons are displayed on changes.
In general, these colors have little use in most icons. There are two ways they are used:
If your icon does not fill the entire bounding box, then fill the unused area with the transparent color.
You can draw a shadow under your icon. This is only recommended for Front-Panel-style icons. Do not use this for File Manager icons. See "Optional Front Panel Icon Style" for more detail.