What are Static Resources in Salesforce?

Static resources helps to store upload images, files, zip files, documents, javascript files, Css Files which can be used in visualforce pages. Maximum data storage limit for static resource is 250mb.
An example of a static resource is an image. It’s the same for each and every request. It’s a file on the filesystem that doesn’t require any processing – you simply tell nginx send this file as-is to the user.

The user interface in a Visualforce base can display dynamic content the value of which keeps changing based on user responses. But there are times when we need some content which should not change with the change in values of other components in the page. For example, an image file may be required to remain constant. Such content which cannot be changed in a page is known as a static resource.

Following are a few static resources in Salesforce −

1. Images
2. Javascript Files
3. Flash files
4. CSS files