How to insert image / photo from iPad into editable PDF

Hi,

We created an editable PDF with some text fields but also some image / picturee fields (to add a few image files to the PDF while on the road after an on-site visit).

All fields, including the photo fields, work fine on Windows. On Apple devices however the text fields (obviously) work fine but the image fields don't work. In Windows they open a brower (Select an image). Within iOS there's nothing like that... Nothing opens, nothing to be selected.

Anyone knows how to add photos from iPad of iPhone in the editable PDF?
Is there a way to easily add the Apple pictures to the PDF?

Thanks for an answer / solution.