Refactor image download script to track and skip previously downloaded files based on unique key and consistent naming
- Added logic to use unique key from JSON data for consistent filenames and tracking
- Improved file existence check to skip downloading files that already exist in the directory
- Updated JSON list to store keys of downloaded files for persistent tracking across runs
- Incorporated delay between downloads for smoother processing
- Cleaned up old redundant code and ensured consistency in file naming and tracking