WEB HOSTING SERVER
In simple terms, a web server is a computer that stores, processes, and delivers particular types of files and programs to the World Wide Web.

DISC SPACE
The term “disk space” means an amount of computer storage space. Website hosting disk space is the amount of storage you have for your website’s files. These files include any programs/systems (like WordPress), images, documents, video, etc. How much Disc space you have is based on how much you have purchased with your hosting account.

Each file that is uploaded to your web server uses space. How much space it uses is equal to the size of the file. For example, if you upload a photo that is 400 x 400 pixels and 72 dpi would be approximately 50kb and therefore use 50kb of hosting disc space. Likewise, if you upload a photo straight off your high mega pixel digital camera or cell phone, your one photo may use well over 2000kb of space.

The amount you need for your website is generally determined by how many pages your site will have AND how many images it will have. Content Management Systems, like WordPress, also uses space. If your site has a blog, your hosting disc space requirements will change with time as you add posts, especially if you intend to leave all posts on the site – meaning that you do not plan to delete old posts. Note: Deleting old posts does not remove the photos that were added to the post. Photos must be deleted separately. If you are using WordPress, here are some directions: https://en.support.wordpress.com/media/deleting-files/

BANDWIDTH
Your hosting account will have a set MONTHLY allowance of bandwidth. The count for bandwidth used will reset at midnight on the 1st of every month.

Using the 50kb example above, every time that image is downloaded, it uses 50kb of bandwidth. The image is downloaded every time someone views a page that the image is on. If your page is visited by 10 different people in one day, the bandwidth usage for that day, for that one image is 500kb. Likewise, for the 2000kb example, the bandwidth used would be 20,000kb!

There is a WordPress plugin, WP Super Cache, that helps to keep bandwidth usage down by caching your pages/posts. You just have to REMEMBER to turn it off if you want to be able to see your edits, then REMEMBER to turn it back on.

OPTIMIZE YOUR IMAGES (Here’s one way to do that.)
If your website loads too slow, your visitors will leave.

The more traffic your site gets (which is a good thing!), the more bandwidth it will use. The more pages and images you have, the more bandwidth it will use. If you don’t optimize your images to 72dpi AND don’t keep them down to the actual size (in pixels), your site will use more bandwidth. It will load SLOW. And, if your visitor is using their cell phone, it will use much more of their data than necessary.

In a sense, bandwidth and cell phone data are very similar.