@LumpyI do this all the time (i.e. once for each of my 34 SOL stories), so I can provide some real-world examples, though mine are only in html, since I like to get fancy with my usage:
< p class=Center>< span align="center">< img src=">image located on disk< "
alt=">Text to be read aloud for visually impaired readers< ">< /span>< /p>
Again, virtually no one ever gets this detailed, but:
The center command places the image in the center of the page,
the span command is exclusively for Apple devices, which are too dumb to recognize a plain html center command by itself
The 'image source' command, which tells the html code where to locate the image from so it can add it to the resulting html file
and the following alt= command allows blind readers to tell what your image details. Feel free to drop any of these you don't need (only the center and img src="" are needed for SOL posted files, but this is a pretty fool-proof usage, which hasn't failed me yet (i.e. the only time is has is when I either screw up the location, or a move the required files before posting!).