Alright. I *think* i know what your problem is.
OK. You first start out with an index.html file. You can create one of these yourself. Seeing that you are new to html, you can use any editor to edit this file. IF you are new to Linux too and are a windows guy, i would even recommend going as far as using Word as an HTML editor. It is a great WYSIWYG editor. (What You See Is What You Get). I wouldn't suggest tackling getting to understand Linux and html at the same time LOL.
Open word and create a file.
Type in something like:
"hello world, I am a cool guy. Look at my picture!"
Now, SAVE the file as index.html...don't forget to change the extension. OR Optionally, there is a drop down that says 'Save as web page' which might be easier.
Now, I believe there is a way to View the HTML SOURCE CODE in word. I *think* it is in View - HTML Source or somewhere around there.
Bingo, all of the html coding. Now somewhere in the <body> of the page, put this
<img src="yourpic.xxx"> xxx can be .gif .jpg .png....etc etc..
Now SAVE the file again.
Now all you have to do is upload the file index.html AND the yourpic.xxx....(The trick here is to make sure the INDEX.HTML file and the PICTURE are in the SAME DIRECTORY when you upload it.)
Now go to your www.geocities.com/whatever/blah/blah/index.html
and you should see your pic and the quote above. Test that out and then play with it and you will learn as you play with it.
*sips coffee and ligtts a smoke*