”cv2.imencode“ image-save-paths which have Chinese name fix

[yeshanliu]

🛠️ PR Summary

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🌟 Summary

Improved image saving functionality in YOLOv5's detection script.

📊 Key Changes

• Altered the method of saving images from cv2.imwrite() to cv2.imencode().tofile().

🎯 Purpose & Impact

• 🛠️ The purpose of this change is to enhance compatibility and reliability when saving images across different operating systems and file systems.
• 🚀 Potential impact includes smoother user experience due to less chance of save errors, particularly on systems where cv2.imwrite() might encounter issues with file paths or permissions.
• 💾 Users should notice no difference in their workflow except for a potential reduction in save-related issues.

[yeshanliu]

#6979 fix the loading problem, this PR fix the save problem.

[yeshanliu]

#7139 already fix this.