Faster --img 64 CI tests

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Refinement of automation tests to reduce resource usage.

📊 Key Changes

• Reduced image resolution from 128 to 64 in training, validation, and export procedures.
• Increased batch size from 16 to 32 in training and validation.

🎯 Purpose & Impact

• Efficiency Boost: Lower image resolution reduces computational requirements for tests.
• Faster Execution: Increasing batch size may speed up the testing process.
• Resource Optimization: Changes likely to decrease the usage of CI resources, allowing for more parallel jobs or reducing costs.