Uploading pictures-adding widgets

I am creating a website for my online jewelry business. I uploaded the pictures of my jewelry and am now placing Add to Cart widgets next to each piece of jewelry. Because I have so many pictures in one category, it's taking a long time to scroll down. Also some of my pictures are blank now, even though the description is there.

Is that because my pictures are too large? Do I need to save them for web?

Any thoughts or help would be appreciated.