Windows 8 behavior with opening all image files in a folder

Windows 8 behavior with opening all image files in a folder

I have a lot of comics in separate folders that I want to open with my app
of choice, CDisplay. I've changed the Open With to use CDisplay, which
works properly for single files and multiple files, but not all files in a
folder. When a folder has multiple image files in it, and I select all,
then Windows 8 opens the Print dialog instead of the preferred app. What
should I do to make Windows 8 open all the files in the app instead?
One workaround is to zip each folder separately - CDisplay will open
those. I'd just like to get Windows 8 working sanely...