smallest filesize for transparent single pixel image

Question

I\'m looking for the smallest (in terms of filesize) transparent 1 pixel image.

Currently I have a gif of 49 bytes which seems to be the most popular.

But I

Answer 1

You shouldn't really use "spacer gifs". They were used in the 90s; now they are very outdated and they have no purpose whatsoever, and they cause several accessibility and compatibility problems.

Use CSS.