Actually, there is no rule stating that you'd need any permission to make or draw an icon for a model by looking at the
Icon Submission Rules and
General Resource Rules, dunno why some of the reviewers often ask for it. If they ask because it's just a screenshot, the moderation is obvious: substandard.
Respective rules are just there to specify the different position of a
drawn icon and a
heavily modified screenshot, which would be approved if they meet the standards, or a
pure screenshot, which would go to substandard; to separate quality content from none-standard ones. General icon techniques matter is another thing (that would set the bundle to awaiting update, which would give an opportunity to the author for an improvement, which is good nonetheless). This is just purely a screenshot, so went to substandard. That's all!