我轉換後原本的圖片可能會變成全黑色，該如何處理。 [World Economic Outlook_IMF-40.pdf](https://github.com/user-attachments/files/18725016/World.Economic.Outlook_IMF-40.pdf) [World Economic Outlook_IMF-40-mono.pdf](https://github.com/user-attachments/files/18725014/World.Economic.Outlook_IMF-40-mono.pdf)