I am having a hard time replicating the second image style in the first. The football field image needs the black to be gone and be replaced throughout the image with a white color. What is the best way to do this in Photoshop and get the same result as the second image?
Image To Convert
Another approach would be to invert the colors (CTRL+I), then add a new layer of pure white (or the gradient @JohnnyKutnowski suggested). Reduce the white layer's opacity slightly to let the image show through. I set my white layer's opacity to 88% and this is the result:
I think your approach isn't the right one in this case.
To achieve what you see in the second image, I would go for a gradient map on the original image with a gray to white gradient. I'm sure that's exactly how they got to that result.
It's easy to do, just add a Gradient Map Adjustment Layer, and choose the colours in the gradient selector.
That being said, to select a colour and than change it, I usually go with
Select > Color Range... and adjust the fuzziness to my needs. But this is what I call a dirty method, just like the Magic Wand.