Some files in folder not shown

[adrian]

I have a folder containing 7957 images that I created yesterday. When xnview starts, it briefly flashes that there are 7957 objects (and this number is displayed in the console message I see) but it then changes it to 6834 objects. So what happen to the ~1000 other pictures? How can I get it to display them all? The "filter by" setting is "images" and "all" so that should not be limiting what is shown.

[xnview]

is it companion files?