DNG files not showing thumbnails preview icon on mac, after reduce/resize pixel count. Mavericks 10.9.2, Photoshop CC, ACR 8.4.0.199. Any Solution?

Question

This is driving me crazy. With today's huge file sizes it seem to me that for the majority of pictures a pixel count of 12-16 mega pixels y more than ok size for editing and make printings; for the professional jobs is a good idea to have the biggest file we can. Due to that i was trying to convert some NEF files to DNG, saving some space in the process, But the impossibility to preview the picture's thumbnails and the file size (it displays 0x0) immediately take me to 1984, (Windows 3.11). and those are bad memories.
     I don't know if this is an apple's or adobe's error, but it needs to be solved.
     Anyone with the same predicament?

Answer 1

Thanks for your insight JimHess.  Someone else on another post pointed out how Photoshop changes the color profile and other things and then trying to make this file into a DNG again confuses Mavericks (and, presumably, other flavors of OS X).  Admittedly, the process I described is unorthodox and not what may want to do.  Thank you.
A.J.: First, I am offended by your suggestion to omit my comment.  I was simply trying to provide help in finding a cause of a general problem people are having across the internet.  That problem, as you pointed out, is that modifying a DNG in some way in photoshop results in the thumbnail no longer being visible.  Your modification is the size.  Mine was not.  But it was a general modification in photoshop and an attempt to reconstitute the file as a DNG that seems to be common theme, whether this workflow makes sense or not.  Additionally, I'm very new to digital photography and tried to be helpful.  I would advise you (as an educator who knows the consequences of negative first-time experiences) to be more mindful that not everyone on here is as experienced as you and everyone can benefit from being clearer in their questions and their comments.
Second, as JimHess pointed out, in manipulating a DNG file in any of the programs in a way that alters the actual file (not changing some setting that is ultimately stored in a side-car file or does not actually alter the photo) is probably the root of the problem.  Changing the file size by altering pixel count may first require one of your adobe products to physically alter the file information in a way that stops Mavericks from being able to recognize the contents as RAW information.  Does this make sense?
Best regards,
Robert