You can add your own widgets and images in the Palette by placing them in the “assets” folder in the root of your project. If needed, the location and the name of the assets folder can be changed per project. To do this right-click on the project in the Project Explorer, choose Properties > Wireframing Settings and change the Assets Folder setting.
You can create your own assets such as components, icons and images. You can also install pre-built assets from Mockups Gallery.
Assets can be shared between projects using project references. Project references can be configured using Project Explorer. Right-click on a project and then select Properties > Project References. This mechanism lets you place assets in a global project and then reference it in other projects that also need those assets.
Next: Mockups Gallery Assets