Cannot import PNG files to Premiere. At all.

I recently started making a montage/mashup of memes in Premiere, and I made a folder with around 50 image files in it.  More than half of these are in PNG format, and when I imported the folder contents, Premiere displayed an error: "Unsupported/damaged file type."

I tried individually importing some of the images.  The other JPG and JPEG files imported fine, but it was impossible to drag, file>import or use any other method to get the PNG files in the timeline.  I tried duplicating multiple PNG files, copying some, deleting and restoring them, but to no avail.  I restarted my PC, and the problem did not go away.

I looked about on the adobe forums, on reddit, and did a google search, but there appear to be no solutions to this extremely irritating problem.  I would love to know if there is either a known fix for it or someone who can help.

I'll  be happy to answer your questions, but so far this is all I know.