Genhtml.exe supports image files with the following extensions (see genhtml -help):<br>
JPG PDF GIF JPEG<br>
Files with this extension are automatically added to index.htm .
<p>

Files with the same name as the image and one of the extensions htm txt (see genhtml -help) will be opened and the contents of these files will be added to index.htm.<p>

This allows you to add comments to images. A WEB index server can be used to add the text-files to make the documentation searchable!<p>

On the opposite you may enter the text into an editor and screen-shot this if you have to be  very fast in documentation. But this approach has the disadvantage that an indexing server might not find any keywords.