01. In order to host a background image for your website you will need to find a place that will offer you space. We can recommend the site 250 free or you may also check out the following link for various other resources. This will give you more than enough choices for free hosts.
02. Once you've found a place to host your images, you will need to register. All this requires is a simple email address in most cases. Free services do not require you to enter credit card information. If you are asked for a credit card number we suggest you find another place.
03. After you have registered, you will be given instructions PER site on how to upload (move your pictures from your machine to their server) your images. Please do not ask in this community for instructions on how this is done. Most of these places are very intuitive - anyone can do it if they spend the time to read their instructions on how it is done. Usually it's as simple as clicking the 'Browse' button, finding the place you saved the image, clicking on it, and then clicking 'Upload' (or a similar button).
04. Generally a service will give you a 'link' to the image you have uploaded. Click on the link and in the 'Address' bar of your web browser, copy down the web address (or URL). You will take the URL and copy it (exactly) into an email to send to whichever designer is working on your layout. That designer will then make the necessary changes to your code.
05. Please DO NOT continually change hosting services. If a company has problems and is no longer available, we may be able to help, but this will depend upon our backlog. We may or may not save copies of your images in case you lose them. We strongly recommend you save a copy on your own machine just-in-case. For those concerned about bandwidth, all hosting services that provide free services allow for more than enough bandwidth for one livejournal. You should have no problems with service limitations where that's concerned.