I have a picture with a border, I want to cut the center out and just keep the border to put around another picture. Using Adobe Photoshop CC. I've tried cutting out the middle with a rectangular marquee tool and using the quick select wand, but neither are giving me the results I want.
On the top menu
Then click on any white part of the image and move the tolerancy slider to get more or less accurate on the selection of the color.
when you click OK you'll get a selection of all the white color on the image, if you press delete you'll remove all the white from the image.
Instead of the magic wand tool you could try the magnetic lasso tool. This tool will snap to the edges of the border, but will not select the white background behind the border.
If you want a bit more refined result you could invert your selection and apply a slight feather to it. This will make the line a bit smoother. Or instead of a feather you could use the refine selection option to further optimize your selection.
For better results, you could use pen tool instead of magic wand tool in Photoshop. Using pen tool create shape around the border and than make selection of it. After selection just crop it using ctr+shift+i to invert selections. It will give you a border with more refined result.