This is a new problem for several months. Cannot see mesh for reference images Blender 2.80. Did not have this problem with 2.79?
Background images as we used in 2.7x are not available in 2.80.
Now when we load a reference image, the image is attached to an empty which displays it in the viewport. As it is an object you can move it in front of or behind any other objects or hide it when not being used.
We can also make the image transparent by adjusting the image properties for the empty.
Note that cameras now have background image properties, this allows an image to always be aligned with the camera view. These settings have a depth option to display the image in front of or behind the scene.