Chess symbols are part of Unicode.

Instead of using images

Digital image

A digital image is a numeric representation of a two-dimensional image. Depending on whether or not the image resolution is fixed, it may be of vector or raster type...

, one can represent chess pieces

Chess piece

Chess pieces or chessmen are the pieces deployed on a chessboard to play the game of chess. The pieces vary in abilities, giving them different values in the game...

 by symbols that are defined in the Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 character set. This makes it possible to:

• Use Figurine Algebraic Notation
  Algebraic chess notation
  Algebraic notation is a method for recording and describing the moves in a game of chess. It is now standard among all chess organizations and most books, magazines, and newspapers...
  
  , which replaces the letter that stands for a piece by its symbol, e.g. instead of Nc6. This enables the moves to be read independent of language (Algebraic Chess Notation
  Algebraic chess notation
  Algebraic notation is a method for recording and describing the moves in a game of chess. It is now standard among all chess organizations and most books, magazines, and newspapers...
  
   lists the different names and letter abbreviations of pieces in several languages).
• Produce the symbols using a text editor
  Text editor
  A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
  
   or word processor
  Word processor
  A word processor is a computer application used for the production of any sort of printable material....
  
   rather than a graphics editor.

In order to display or print these symbols, one has to have one or more font

Font

In typography, a font is traditionally defined as a quantity of sorts composing a complete character set of a single size and style of a particular typeface...

s with good Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 support installed on the computer, and the document (Web page, word processor document, etc.) must use one of these fonts.

Unicode codepoints and HTML

Chess symbols are part of the Miscellaneous Symbols block.