Resolution determines the number of pixels that make up the entire image. The size of the image is whatever you you want to display it in. They really are not related. You, the user, pick each factor.
So, for the big lumpy pixels, just drop the resolution. On your screen, the image will probably shrink because, no matter what resolution your image is, your monitor will want to display it at 72 Pixels Per Inch. Just "Zoom in" with the magnifying glass tool and the image will get bigger so that you can see the big lumpy pixels.
In Photoshop, you can go to the image menu and change the image size to whatever you want and at the resolution you like. That way, if you are going to print the image, it will show up on the paper at the size you selected.
Designer, Illustrator and Desktop Publisher for over 30 years