Cannot insert certain png files

Each time I drag this (particularly large) png file into Unity, I get this error:

Could not create asset from Assets/runway initial - Copy 2.png: File could not be read
UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag(HierarchyProperty, Boolean)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

It works if I cut the resolution by 75%.

Here is the image for reference. It is 49868 x 800 pixels big.

I’m pretty sure the maximum size of images is 4096x4096.

There isn’t any real reason your png should be as large as it is.

I would look at cutting that runway into square tiles.