Suggestion: Make the camera.snapshot service fetch image from still_image_url when it is available. Fallback to the camera stream when still_image_url is not available. Or maybe make it configurable. The point is in most cases the substream in DVRs and IP cameras uses smaller resolution than the still image. For example my Dahua DVR produces maximum D1 substream, but it can do 960H still images. However camera.snapshot service can not benefit of the 960H quality.