the user will be "forced" to use some kind of software
regardless of how you transmit the text and picture to
her.
the simplest solution for her might be an email with an
attached image.
if you want to combine the text and the picture in 1
file, you need an archiver. the recipient will, likewise,
require an un-archiver to separate the text from the
image. (.zip files is an example of files which have
been archived for one purpose or another).
most computers, regardless of their operating system,
will be able to handle the email + attachment solution. an
un-archiver compatible with the one you use to archive
the files in the first place may have to be downloaded
and installed, depending on the user's system.
if your users don't know how to use word or a pdf reader,
they may well be unfamiliar with an un-archiver (eg, zip).
archiving a number of files before sending them to
someone affords some advantages for the sender and
the recipient. but both need to know how to use it.
since you've already said you don't want users to be forced
to use special sofware, i don't see how you transmit the
text and the image except by e-mail. it's certainly a very
reliable and simple method. even if you archive the files,
you still have to e-mail the archive, and the recipient will
have to un-archive it. you add a level of complexity to a
very simple operation.
if you were sending dozens of files and accompanying text
for each one to individual users, then, for your own sanity,
you would need to consider archiving.