After modification of a DNG picture (in camera raw editor of Photoshop Elements) I don't see the modifications in windows explorer or windows foto app. All I see is the original -non modified- version of the picture. When opening the DNG file in the camera raw editor, the modified picture appears. The PNG file is created by adobe DNG creator
Editing a DNG image doesn't change the image data, just appends a set of instructions describing the edits to the file. Those instructions for Adobe products are only readable to another Adobe product. Solution: Export to JPEG, TIFF, etc if you want to see edits in another app.
You're seeing a tnumbnail that isn't affected as the 'edits' are parametric in the DNG and you have to render (process) into an actual image data file Windows can 'see' like a JPEG or TIFF. The parametric instructions are proprietary (true for all such edits of raws in every raw converter).
Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"