Assert --image-weights not combined with DDP

[glenn-jocher]

Improved error handling when users combine incompatible --image-weights argument with DDP. Resolves issues #2461 and #3265.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved validation of training options in YOLOv5 DDP (Distributed Data Parallel) training mode.

📊 Key Changes

• Added a check to ensure the --image-weights argument is not used with DDP training.

🎯 Purpose & Impact

• This change ensures the user is informed about incompatible training options, which helps prevent potential errors during the distributed training process.
• This clarification could lead to smoother user experiences and fewer issues for developers working on training models at scale. 🔄