Macmanx said "No, you want your theme's sidebar.php file. Go to the Presentation menu and select "Theme Editor"."
In the "Theme Editor" there are three 'Sharepoint Like' theme files: Styles sheet, Comments Template, Main Template.
While I did not make the changes using the 'Themes Editor," the changes that I did make are reflected on the Main Template. (I had not discovered "Themes Editor." I've only been using WordPress since Friday. Php and blogging are new to me. )
To try to figure out how to make the change from your original suggestion, I first used ftp to search the online files in my theme for sidebar.php. When I couldn't find sidebar.php there, I searched the the WordPress files. Then I decided to investigate my downloaded copy of the theme folder -- I searched the contents of those files.
The way I actually made the change was to cut and paste into that index.php file which I uploaded that using ftp. Since my photo is now showing on my blog (although I will resize it if I've done this correctly), I'm hoping it's going to be ok. I guess the question in my mind now is, will cause any problems for me later?
Also, I notice that there are some foreign language notations on the posting section of this blog. Will these disappear when I post my first message?