This is the official manual for the latest Org-mode release.
HTML export can inline images given as links in the Org file, and
it can make an image the clickable part of a link. By
default1, images are inlined if a link does
not have a description. So ‘[[file:myimg.jpg]]’ will be inlined,
while ‘[[file:myimg.jpg][the image]]’ will just produce a link
‘the image’ that points to the image. If the description part
itself is a
file: link or a
http: URL pointing to an
image, this image will be inlined and activated so that clicking on the
image will activate the link. For example, to include a thumbnail that
will link to a high resolution version of the image, you could use:
If you need to add attributes to an inlined image, use a
In the example below we specify the
title attributes to
support text viewers and accessibility, and align it to the right.
#+CAPTION: A black cat stalking a spider #+ATTR_HTML: :alt cat/spider image :title Action! :align right [[./img/a.jpg]]
You could use
http addresses just as well.
 But see the variable