Added imageType property to imageContainers, so that they can more easily be validated (for example, when trying to add an image to an existig imageContainer).
Added imageType property to imageContainers, so that they can more easily be validated (for example, when trying to add an image to an existig imageContainer).

OpenWebslides/OpenWebslides,OpenWebslides/OpenWebslides,OpenWebslides/OpenWebslides,OpenWebslides/OpenWebslides