• What are Challenges? 
• What types of challenges are there?
• What are the rules for Challenges?
• What is a Partner Challenge?
• Where can I find my Challenge submissions?
• Can I hide a Challenge submission from my profile?
• Why was my Challenge submission rejected?
• My submission was rejected. Can I submit another image?
• Can I remove a submission from a Challenge?
• How are winners chosen for Challenges?
• How can I vote in a Challenge?
• What is the Winners' Gallery? Where can I find it?
• What is the Challenges leaderboard?