Emojis look like images, or icons, but they are not.
They are letters (characters) from the UTF-8 (Unicode) character set.
To display an HTML page correctly, a web browser must know the character set used in the page.
This is specified in the tag:
Many UTF-8 characters cannot be typed on a keyboard, but they can always be displayed using numbers (called entity numbers):
The < meta charset="UTF-8"> element defines the character set.
The characters A, B, and C, are displayed by the numbers 65, 66, and 67.
To let the browser understand that you are displaying a character, you must start the entity number with and end it with ; (semicolon).
Emojis are also characters from the UTF-8 alphabet:
Since Emojis are characters, they can be copied, displayed, and sized just like any other character in HTML.