...as nothing will function interactively unless the Body of Message is changed from the default Plain to HTML.

A very good site for those starting out is http://www.w3schools.com/html/default.asp. Although light on explanation, examples of every HTML tag (3.2) are shown in situ within an HTML document to indicate location and use - this is shown with a corresponding browser page to demonstate the result.

I've found it a helpful reference at times, Patricius.

Your query re referencing a graphic located offsite is a little unclear. If you want to show the graphic within a webpage or your post here, the coding you would use would be this:

< a href="http://users.tpg.com.au/lisekool/horus_glyph.gif">< /a>

There are two problems with this. One is that unless this is referenced from your own external website such as is the case here, you are 'stealing' bandwidth from another's site. I think that's the term used. Secondly, the image unless very small will not sit neatly within your text.

Re resizing existing graphics: not a wise idea as it negatively affects the quality. You can get away with it to a certain extent if you reduce the size but never enlarge particularly with a web graphic of 72ppi (pixels per inch) as the pic will become very pixelated. This comment of course refers to graphics that are manipulated within a graphics program to affect size.

You can influence image size by changing the height and width attributes within the image tag itself but the same problems arise and it's not recommended - it still degrades the image in situ. I think I'm correct in saying that the kilobyte size remains the same whether the pic is enlarged or reduced in size. This could be misleading if you have limited webspace here in your image gallery and hope, by reducing sizes, to add more graphics.

I hope this helps to answer some of your questions *s*