I have had this issue on 2 separate computers for months now. When importing a JPG or PNG and then dragging it onto the timeline, the software no longer reacts to most clicks. E.g. it does not react to clicks in the timeline and it does not activate a clip when I click on it. It accepts certain clicks, but not others. It is difficult to explain which clicks are recognized and which ones are not. As soon as I (somehow) manage to click on the imported picture and delete it from the timeline and from the media library, the problem is gone. The likelihood of this bug is higher on my PC than on my laptop, but both devices have the same problem. It clearly is a bug in the software and from reading the posts from the last years, this bug has been there for years now. Any ideas how to fix this? Thanks!
I've never experienced what you are experiencing but one thing I am aware of is that very large images can cause problems in Premiere Pro. So my question is what size are the images you are importing. And do your results differ if you size the image down to say something like 2000 pixels wide at 72 dpi?