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Allow adding/editing/deleting PNG embedded comments

Posted: Sun Dec 03, 2023 9:30 pm
by exener
PNG files can have embedded comments. XnView MP will correctly show them in a file's properties dialog box.

However, I don't see a way to easily add/edit/delete PNG embedded comments for an existing image.

Can such functionality be added, please?

Related: viewtopic.php?f=60&t=46519

Re: Allow adding/editing/deleting PNG embedded comments

Posted: Sun Dec 03, 2023 9:45 pm
by michel038
Perhaps right click > Metadata > Edit comment (Ctrl D) ?
Select the appropriate field and edit ...

Comment is a file property, not a "classical" metadata (exif, iptc, xmp)

Re: Allow adding/editing/deleting PNG embedded comments

Posted: Mon Dec 04, 2023 6:31 am
by exener
michel038 wrote: Sun Dec 03, 2023 9:45 pm Perhaps right click > Metadata > Edit comment (Ctrl D) ?
Select the appropriate field and edit ...

Comment is a file property, not a "classical" metadata (exif, iptc, xmp)
Thanks for your reply. That's very helpful and it seems to work. (For others: you may not have the Metadata menuitem in the context menu, but it can be added, or may be available in the top menu bar.)

BTW, I was using the "Properties..." menuitem, and the embedded PNG comment is listed in the "Properties" tab within the ensuing dialog box. But, alas, it is read-only. I think it may be helpful to have a button, within the "Properties" dialog box, to open the dialog box you referenced (or, even better, give the "Properties" dialog box read-write functionality).

Note that PNG embedded comments are stored directly within the PNG file itself, not in an alternate data stream, a separate metafile, or the drive partition's (or folder's) file table. Thus, I'm confused as to why you mentioned that they are "file properties". As you noted, they don't seem to be "classical" metadata like Exif, but they also don't seem to be typical file properties either, which are usually stored by the OS outside of the primary data stream of the file itself. But given your avatar, it's possible you know a lot more about this topic than I, so I'm interested in learning from you.