How to add pixels in a website?

Question

Nothing in description.

Answer 1

Individual 1px by 1px

Answer 2

I don't know what that would be useful for but there are several ways to do this:
Add 1px by 1px image with img element.
Add div element and scale it to the desired size using css.

Note: if you want to manipulate many "individual" pixels the described methods are not really good for that. Then it would be better to use a canvas element and draw on it using JS.

Answer 3

What do you mean by pixels? Like individual 1px X 1px or something else?