Image Collector Throws NullReferenceException

[dansiegel]

Description

The CollectImageAssetsTask encounters a Null Reference when determining the correct search paths if some conditions are not properly set.

Reproduction Steps

{
  "images": {
    "directories": [ "images" ]
  }
}

Since no conditional directories are set the conditional directories will be null and this will throw an exception.

Expected Behavior

this should collect images in the images directory without error

Actual Behavior

this encounters a NullReferenceException as there are no conditional directories.