This investigation was prompted by a need to quickly check the captions saved in JPG files. After some exchange on the linux _at_ oclug.on.ca list, I recorded what I found, including a nice simple tool built on the
feh package. See
scanjpgwoes.pdf. Because the Irfanview program for Windows (32 bit particularly) is useful for both Linux and Windows, documentation of how to use it to view JPG Comments in full-screen mode is presented separately as
viewjpgcmt.pdf.