I need to invert and crop a lot of images in a raw. Would it be possible to batch edit pictures?

Hi! For my daughter's univ studies, I need to recolor pdf courses so as to save ink. Yhe only solution I found is to convert them to black and white images, invert them in photoshop and crop off the now black marges before printing. However I have a lot of pages to do, 2 pictures on one page, and photoshop closes after each image without the possibility to batch invert or batch crop several images in a raw. Could you help me, please? It's quite urgent and important and may help thousands of students! :===(