Thorsten Lemke, author of GraphicConverter, seems to be very responsive when it comes to feature requests and bug fixes for his product. When I earlier encountered an apparent memory leak with the “JPEG -> Remove double orientation tags and reset them” feature, he quickly provided me a beta to try out, which helped somewhat with this problem. (It will still crash on tons of photos, but not for the same reason. The memory leak seems to be gone.)
Anyway, after posting to the GCMAC mailing list, I have been contacted by two folks from Lemkesoft, and now I am trying out a new beta which seems to make the routines that normal just see EXIF also see the “PictureInfo” date. In the “ExifTool” window of GC is a section for File (with modification time), then one for JFIF (resolution and such), then PictureInfo (which has the info from my old Epson camera — I specifically see the date/time and “Sierra Highland” which is a string the camera embedded in the pictures, and one you could customize with the PhotoPC software.
Using this new beta, I can now simple select some photos and do “JPEG -> Set EXIF Date to File Creation Date” which seems to honor the PictureInfo date (though the wording implies it would use the file system Creation Date, so maybe this needs to be changed).
There may still be some issues — in testing, I find it is now adding multiple “File data and time” entries to EXIF, so I’ll work with Lemkesoft on this until we get it hammered out.
Very nice response!