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

http://polpo.org/blank.gif is a 37 byte transparent GIF made with gifsicle.

In css-ready base64 format:

data:image/gif;base64,R0lGODlhAQABAHAAACH5BAUAAAAALAAAAAABAAEAAAICRAEAOw==