In the past we have had 4 or 5 attempts by people submitting pictures that arn't really theirs, so to protect your images we recommend water marking them

Using PAINT.NET, choose the text option then choose a transparent colour to write with,

Then write your name, email, or your website address on top like this:
Note: Do not write it at the bottom because it can easily be cropped out

So at least this way people will always know who the real owner is!