The suggestion to post a link on line was NOT to see a correctly coded page, rather it was to diagnose the problem you are having. Code snippets only provide a portion of, not the whole picture.
If you have a Web host, just post a sample test page... one that can be removed later.
I'm seeing a couple of possible errors... which could easily be confirmed and fixed with a link to the actual page......
First, this is an invalid address:
If the file is on your local machine... then there is no "http" used to access the file.... so just use a relative address. Relative could be thought of as... "starting at".
Major posted an example of a "relative" address..
background: #81bef7 url('models/webtemplate1.jpg') no-repeat center fixed;
That is.... relative to THIS file (starting at this file) the path to the img is (inside this folder) "models" subfolder, then the "webtemplate1.jpg" file
... starting from THIS file, go to subfolder "images", then subfolder "models" to find the file.
But note that the path to images coded in external CSS pages is "relative" (starting at) the css file, while images placed on Web pages using <img src"..... are "relative" or starting at the Web page... also note that in the CSS, single quotes are used, while if on the HTML page, double quotes.... not a mix, as in your second post:
I put <img src='spencer/pictures/models/webtemplate1.jpg"/>
So the path to the same image could vary depending on if it was coded into an external CSS file or directly on the Web page.
If you are correctly pathing your images according to these guidelines and the image STILL does not display... then you have a problem with the image.
The image may be a PhotoShop .psd file or the .jpg was saved with color mode CMYK, instead of RGB, etc.
All of which could easily be diagnosed if only we had a link to the actual page.
Eye for Video