Login & authorize with Instagram. This assures that you are the owner of the pictures you want to submit in the next step.

Here you can select photos from your stream and submit them to current challenges.
(You can also authorize InstaChallenge to use the challenge’s hashtags to automatically submit the pics you have tagged.)

With your submission you declare that these are your photos and that no other rights are violated. The photos you submit to the challenge(s) shall be made with your mobile phone. And please pay attention to the special rules of each challenge you participate.
The list of current contests, their deadlines, tags and descriptions could be found on the challenges page.