> How do you put up JUST images that are not part of a HTML file?
You can put images into a collection, and assign metadata to them in the
standard way. To process the images, you need to put ImagePlug in your
plugin list, before the HTML and Word plugins. ImageMagick needs to be
installed for this to work.
> Can we point to a URL without storing media items/artefacts on a local
In general, Greenstone likes to have a "document" (textual, image,
multimedia etc). You can assign metadata to it, and display the document.
If you have a metadata element with a URL in it, you can link to it
using format statements. eg instead of linking to a greenstone document
using [link][/link], you could do something like <a href=[URL]></a>.
You could build a collection using local files, storing the URL
metadata, and then throw away the original files, and only link to the
URLs. Building a collection without the source documents at all is a
little bit trickier but can be done - using bibliographic files, or
perhaps a new plugin. However, if you have textual documents and want to
search the text, you will need them locally to extract the text.
If you give a more specific example of what you want to achieve, we can
give some suggestions of things to try.