Resizing images so they won’t be cropped in the hero banner slider

Hello there! I’ve been getting a bit frustrated in trying to have the entire image show in a sliding banner and not get cropped or cut off. I’ve tried resizing the image several times through Photoshop, but it seems that there is some kind of code that just wants to crop my images nevertheless. I also tried to get a smaller picture to appear bigger for uniformity as well (the picture of the girl in the part that says Education), and can’t get that to size up even through changing the image size in Photoshop. Can you help me? I am very grateful for any assistance so that I can finalize this website!