Refreshyourcash.com provides a good explanation about your browsers cache “Your browser has a folder in which certain items that have been downloaded are stored for future use. Graphic images (such as buttons and icons), photos and even entire web pages are examples of items which are saved or cached. When visiting a web-page your browser checks if a copy of the files on the page is in its cache already.” This saved time by serving you a page which is stored locally rather than downloading the page again.
How to clear cache
Sometimes the cache needs to be cleared, if the local version of the web-page is out of date or if its location has changed. Some settings on sites will be deleted. For example, if you were signed in, you’ll need to sign in again. In addition, some sites can seem slower because content, like images, will need to be downloaded again. Click here for instructions on how to clear your browsers cache.