Hey, I'm super new to this site and decided to enter a contest. I took the picture myself, and then further enhanced it. This might sound like a stupid question, but someone told me I need to source - how do I do this?

The only stupid question is the one unasked.

Look at the front page of the site. On the left are the three active contests so click on one of those links. It will take you to that contest and in the upper right hand area is the "source" photo to be used in the contest. Click on the image and you can download it to start chopping.

You should read the FAQs here that should answer most of your questions.

Welcome and good luck.