There is a special interface for organizing the images you want to use on the dashboards.

1. Tabs for the categories you want to assign for your images
2. Import library - to load saved earlier other library
3. Add a category
4. Upload new images to the current Category. You can also drag&drop files from your file explorer
5. Preview images
6. Select/Deselect All checkboxes. You can use Ctrl key to toggle individual images

After selection, new options will be offered:

1. Delete
2. Move (to another category)
3. Download as a library for future use