If we want images converted to "data" we should use option encoding images

Base64 format encodes images to the binary string where each symbol represents a single byte

Algorithm is encoding a image data into 'ASCII' (abbreviation of American Standard Code for Information Interchange) string that is untyped reference, or descriptor, of a block data.

Characters to encode an images are "a-z", "A-Z","0-9", "+", "=" and "/"