Why doesn't clicking on pngs open Preview?
A few weeks ago, Preview started going MIA. After years of faithfully showing pngs, jpgs, etc. when I click on them, Preview ignores them.
(The click on the image files causes the obsolete HP Photosmart Studio to slowly rise up and crash.)
To open a file in Preview, I have to open Preview and use its menu commands or drop the file on the Preview icon.
How can I reset my system so clicking on pngs etc. will open Preview without any fuss?
Mac mini, OS X El Capitan (10.11.6)