12.3.4 Rarely used HII protocols

There are two rarely used HII protocols: HII Font Protocol, and the HII Image Protocol. Though rarely used, understanding them is important HII Font Protocol

The HII Font Protocol provides functionality equivalent to the String Protocol but manages fonts instead. Fonts consist of glyphs, bit-mapped representations of characters. The characters are referred to by their Unicode weight, which is to say their corresponding binary value. For example, weight 0x0030 is a "0" (zero). A font is a series of glyphs bound together by name, size and similar visual characteristics.
The default font is the system font, which is 8x16 and 16x16 (for wide characters). Latin-1 characters in this standard font are provided by the system firmware. If a driver uses other characters, including e.g. Chinese, Korean, Hindi, Arabic, Hebrew, etc. A driver must provide all of the characters it uses. The build tools determine the actual characters used. Other fonts are identified by GUID.
TIP: It is strongly recommended that the system font be used for reasons of size and consistency.
Unlike strings, fonts are not separated by handle. When a driver provides fonts to the database, the new glyphs are merged with existing glyphs, provided that they are the same font. This means the display of a driver's data may use a different driver's font characters. HII Image Protocol

HII provides simple support for images like graphical pictures and simplistic animation. There is no requirement for browsers to support graphics. The browser in EDK II does not support graphics and most setup browsers do not support graphics simply because of size requirements. The exception is for splash screens (banners).