Not sure where the appropriate place is to post but I requested a custom ship image (large & small) for an Assassin Corvette. A lovely combination of blue/red/carbon and with nothing offensive or against any rules to which I am aware of.
[General] 2 Year 8 Day 89, 5:24 Your custom image for entityID: 112849 has been denied
[General] 3 Year 8 Day 88, 18:19 You have submitted a request for custom ship images for shipID: 112849
Would need to goto the Website Suggestions forum to suggest that improvement.
Also instead of coming here, you could always hunt down one of the Art Team leaders and ask them how to improve your image so it would be approved. (They have access to the script for approving custom images)