Why does this need an explanation?
In the Stream Deck editor, you can define icon(s) for your buttons; in most cases, that method is sufficient. This method is used in the Mackie Control action when you create buttons that act as Mackie Control switches (Play, Solo etc). As long as static images should be displayed, this method works without problems.
Regarding faders and V-pots, the Mackie Control action can create dynamic images that give a graphic view of the fader or V-pot position and state. In these cases, the plugin creates the images by layering state images upon a background image and displays the resulting image on the button. Unfortunately, the Stream Deck software does not give the plugin any information about which image is selected for the button in the editor. If you select any image in the editor, that image will be displayed no matter what the plugin does.
So... for the plugin to create and display images dynamically, all the image information must be defined directly in the plugin, not in the ordinary icon selection in the editor.
Faders and V-pots
Mackie Control faders and V-pots work very differently.
A fader is very detailed and will send a value between 0 and 16.386, depending on position.
A V-pot has 11 LEDs that can be lit in various patterns depending on which function you are controlling. A V-pot sends turn speed rather than position.
Due to these differences, the plugin creates the button images somewhat differently. Since V-pots have 11 LEDs, these are defined as individual images that are layered upon the background image. On the other hand, the fader state is either a painted bar on the background image or a handle image layered upon the background image at a position corresponding to the fader value.
Fader images for vertical or horizontal bars
As mentioned above the background image must be selected in the plugin, not in the editors icon selection. Just click Select file... and locate the file you want to have as background image on the button. (if no image is selected, a simple white backgound is used)
Whenever fader state changes - either by pressing the Stream Deck button or by moving the fader in the daw - a new image will be created and a vertical or horizontal bar representing the current fader position will be painted upon the background image and displayed on the button.
For the pre-defined patterns Ring and Horizontal bar, you only need to select the background image to use. Click Select file... and locate the file you want as a background image on the button. (if no image is selected, a simple white background is used)
Whenever the V-pot state changes - either by pressing the Stream Deck button or by moving the target parameter in the daw - a new image will be created, and state images will be layered upon the background image and displayed on the button.
State images are stored in folders; if you want some other design, you can create your own state image folder. To select the folder for your own state images, you must select a file (any file) in that folder. Unfortunately, no "Select folder" dialog is available in Stream Deck, so we must use the "Select File" dialog. The folder containing your selected file will be used as a state image folder.
Please see the V-pot image files page for details on custom V-pot images.