If you are sure that the content of the PDF file is all images, or if normal conversion does not meet your requirements, then you can try OCR technology conversion.
At the bottom of the conversion page, there is an option about OCR, check it.
Suggestion: Do not check this box in generalOn the bottom of the conversion page, there is an option to open in the File Explorer.
When you check it, the converted files is opened in the File Explorer when the conversion ends.