What is a challenge for you? We all face challenges of some kind. It could be a mental challenge, a physical challenge or an emotional challenge.
This photo represents all of the above to me. Hiking on a trail, having to navigate water and obstacles. How do you get around or through it? Can my body even do it? How do I face my emotional fear?
You can share details of your struggles or keep it simple. It's up to you how vulnerable you want to be with the prompt. It's green week so it might be a "challenge" to even incorporate the color in your image.