Hi!

I'm a maintainer of pdfly, that has an extract-images subcommand, that uses PageObject.images internally.

Recently, a user reported an image compression issue: py-pdf/pdfly#200

I investigated and I think I found what happens:

• in pypdf, PageObject.images invokes PageObject._get_image() that calls _xobj_to_image()
• _xobj_to_image() calls the Image.save() method of Pillow that use a compression of 75% by default: https://pillow.readthedocs.io/en/stable/handbook/image-file-formats.html#jpeg-saving

Suggested bug fix

In _xobj_to_image(), pypdf could simply provide an extra quality="keep" to Image.save().

IMHO this seems like the best default value,
even if that means a non-fully-backward-compatible change to pypdf.

Feature request

Could it be also possible to introduce a way to provide a custom value for this quality parameter provided to Image.save(), please?

Ideally a new optional argument would be great, but I don't quite see how to make this works with the PageObject.images property that returns a VirtualListImages...

Maybe through a global variable ?
Or through a new parameter of PdfReader?