Placed Images Suddenly Become Blurry When Exported to PDF
I am working on a flyer and I have 3 placed images that look just fine while working in InDesign, but become extremely blurry when I export the document to a PDF. My display performance is set to high quality, and all 3 images are PNG and none were edited using photoshop or rotated. They were simply placed directly into the document positioned and sized. The strangest part is that I have been working on this document off and on for weeks and this wasn't an issue until today. I had exported this same InDesign document with the same 3 images at least 10x with no issues like this.
The first image is just a place holder until I decide on which licensed image to purchase, but is still a high quality image and should not be blurry. Here it is in the InDesign document:

and here it is exported into a PDF:

Second Image:

Exported PDF:

And third image (looks like the second one but they are different files):

and exported PDF:

