I am not sure what you want to achieve. Do you want to convert pdf to image or a scanned image to PDF? And do you want to manipulate the PDF or the image? That will make a difference in the solution.
Either way i think you will need a third party java library to do so.
Check out https://stackoverflow.com/questions/4886042/pdf-to-image-using-java for example.
Aspose also offers enterprise quality libraries for such actions, but that comes with a price tag.
If you’re looking for a quick way to convert scanned PDFs to images like JPG or PNG, you can use online tools like image converter. It’s simple, and you won’t need to deal with complex setups or third-party libraries. For advanced customization, a Java library like Aspose can also help, but it’s a paid option