I agree that this would be a useful feature. It can help to distinguish between important, mandatory tasks ("this has to be done/answered in any case") and optional tasks ("this can be done, if desired or if there is still time left").

Maybe more like a if-connection between task and comment/pic ? As if the task should be skipped or selected with no you can choose that comment and/or a picture will be mandatory ?

Let me ask: Is it so that you want to force a user to add a comment to a task? So to finish the task I have to add a note, right?