Add image widget which allows you to switch images to signal state

[sebme]

Potential downside of wither approache, though I am not 100% sure right now how it behaves: caching behavior.

If I close the player and restart it and then load the app I initially see a blank image… Lots of flickering

Are default assets in variables not pre-loaded?

Ability to define if default assets are pre-loaded or not

Right now it seems that the Tulip player does not pre-load its default variable assignments if they contain assets like images or documents. As a result, when the player is started for the first time, the operator will first see a gray blank image before the proper content is displayed. It would be great if one could specify that an asset should be pre-loaded into cache before an app is displayed to an operator to prevent this flickering. [flicker]