Explanation/Reference:
A: The object cache is used internally to optimize page rendering by storing properties of sites, page layouts, and pages. The object cache reduces the amount of traffic between the Web server and a SQL database. This results in higher throughput of rendered pages, thereby increasing the number of pages that can be delivered to clients.
B: SharePoint Server 2013 provides a disk-based cache that stores files that are used by web pages to help them load quickly in the browser, and reduces the load on the database server when it uses those files. These files are known as binary large objects (BLOBs), and the cache is known as the BLOB cache.
The BLOB cache is stored directly on the hard disk drive of a front-end web server computer.
* When using Image Rendition you will have to enable BLOBCache to improve performance
* By using Device Channel Renditions you can create smaller image sizes designed specifically for mobile use. This allows the mobile user to browse the smaller version, increasing the overall performance for the device they are using. Image Rendition enables you to have large files stored within your website along with smaller scaled variations for mobile users.
When using Image Rendition you will have to enable BLOBCache to improve performance From scenario:
* Some employees report that the home page loads slowly. You investigate the issue and find out that the size of some images is very large. You must enable image renditions on the intranet site collection.