This change fixes a small but real compatibility issue in org-noter-pdftools.el by replacing (require 'image-tools) with (require 'image-mode). The old require target appears to be incorrect, which could break loading or runtime behavior for users working with PDF annotations and image handling. In practice, this makes the integration more robust and reduces setup friction for Emacs users.

Updated the PDF tools integration to require `image-mode` instead of the non-existent `image-tools` module so the package loads correctly on current Emacs setups. - zhengqunkoo/org-pdftools