Typographic covers with no imagery at all are very common.
Of course, a selection of books from a different church (or even the same church in a diffeerent month), and from another individual's book case might look completely different.
The point is that what matters is not that it 'looks Christian', but that it looks like the kind of Christian book the ideal reader likes to read (because all Christians do not like all Christian books, obviously).
[Edit: I was looking at imagery only, someone pointed out that the titles of most of those books do make it clear it's a Christian book. The problem is if nothing does.]
|*These fiction books have more saturated, warmer colour scemes in general.|
*The ones written by women all have a large photo of a face. The ones written by men either have no face or a small one.