Images pushed smaller when the browser becomes smaller

Hello!

I'm very frustrated because my images aren't scalable. When my browser is at its full width, it looks fine. However, when I make the browser size smaller to test responsiveness, the image doesn't scale. The image goes from being a portrait image to a landscape image with most of it becoming cropped. This is happening to every image on my site. Please help!!

Are you referring to background images or image blocks?

Please share a link to your site so we can have a look