Geralt_of_Rivia: It's the program or device that creates the file that decides what to write into the metadata or not. While the original png specification did not support metadata current specification certainly do so you are not safer with png than with jpg. It just happened that the program you used for converting the jpg to png either does not support metadata in pngs or was configured to not copy metadata.
While there was an update for libpng in 2017, which enabled the usage of eXIf chunks within PNGs, in my experience, this feature of the extension to the PNG specification, is still, after 6 years, not utilized by the sane (and minimalistic) screen capture and image editor programs that I have used (thankfully). However, this is definitely a concern for people that may be unknowingly broadcasting information that is relatively-sensitive in nature.
There have been other methods for embedding information within other chunk types of PNGs (as well as through unusual means, such as alpha channel steganography), but, this is rare, and would probably need to be added through deliberate action (usually malicious).
OldFatGuy: For all I know the png pics I posted do have the same metadata.
The aforementioned metadata does not seem to reside within your posted PNGs. If you prefer, continue using that program (for PNGs, anyway), or another that explicitly respects your privacy. For Windows, uncertain which applications those might be. Others may have a recommendation.
OldFatGuy: WHY the hell do all of these programs add this metadata to begin with? Sounds like big brother crap to me, as in they are "encouraged" (cough-cough) by governments to do so.
Personally, I agree; for the average person, there really is
zero need. It is unfortunate that it has been standardized (and exploited), as it has been used to stalk, harass, threaten, assault, and, even,
kill. While preparing to share a JPG (if the PNG (even after using a program such as 'pngcrush') exceeds size limits of a given service), I strip all metadata, or convert the JPG to some obscure image format (which is known to only contain image data), and back to JPG/JPEG.