Having trouble resizing images

Does anyone know how to fix the image size? No matter what image size I choose (thumbnail, full, medium, etc) a few of my images are blown up to fill up the full screen. I’ve tried different photos but I’m not sure if I need to maybe standardise the size of all the image for this to work?

I’ve tried both carousel and slider, and playing around with other settings but it doesn’t seem to have any effect on the image size