"J. P. Gilliver (John)" wrote:

For .jpg image files, I can add text notes to them very easily: in
IrfanView, I just (open the image and then) type I (info) then C
(comment).

This doesn't work for the .png file format.

_Does_ the .png format _have_ a metadata text field? If so, what utility
lets you see it, and ideally edit it?

(I'm talking about text that _becomes part of the file_, not that is
attached to it in some "album" type management system: such that it
remains part of the file even if the file is renamed, moved, or even
emailed.)

A decade or two ago I invested a lot of time using IrfanView's Comment
dialog to add info about many of my JPG photos. But occasionally I would
forgot that my other frequently used image editing program PaintShop Pro
8 unceremoniously destroyed them.
https://www.dropbox.com/s/uhsoy8hwu6...oyed.jpg?raw=1

(The much more recent version, PSP 2018, just deletes the comment
entirely.)

Similarly, PSP destroys any IPTC data.
https://www.dropbox.com/s/huwlfei503...oyed.jpg?raw=1

IV save options of course were set to preserve Comments, EXIF and IPTC:
https://www.dropbox.com/s/jr4zo7o5lb...ions.jpg?raw=1

PSP also lost original EXIF data, such as info important to me like GPS
coordinates etc.

I just took another look at Properties. The comment 'Test comment' I
added in IV does not appear using Win 10 FE R-click Properties.

But interestingly some of the test info I had added in the IPTC dialog
*does* appear. However, that doesn't include the caption description,
which could have been an alternative to Comment, unlike Author or
Copyright.
https://www.dropbox.com/s/f42it7l42d...ties.jpg?raw=1

Terry, East Grinstead, UK