A better, larger tagging marker.
Could the tagging marker be larger and more visible (in both preview and thumbnail views)? For example, a light green square (or dot, or tick)?
It hasn't changed for years; it's almost microscopic in size and, for example, very difficult to see on a 4K screen. Furthermore, even when a photo isn't tagged, there's an empty, light square, which is very misleading because it looks almost identical to a tagged photo (the tagged photo differs only by a thin "tick" in the center of this tiny square).
Mockup attached (use slider to see whole picture):
