The discussion centers around a photo contest themed "Cry Me A River," where participants must submit images featuring rivers as the main subject. Key contest rules include the acceptance of only digital photos relevant to the theme, a size restriction of 650 x 490 or 490 x 650 pixels, and a limit of one submission per member. Editing is restricted to resizing and adding watermarks. Participants are encouraged to share their photos via image hosting sites and must ensure their submissions are original. The conversation also includes various members sharing their river photos, discussing locations, and engaging in light-hearted banter about the contest and the beauty of the rivers depicted. Additionally, there are discussions about the geographical significance of certain rivers, with some members quizzing each other on river classifications and flow characteristics. Overall, the thread combines contest participation with a shared appreciation for river photography and geography.