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

Transparent dot, 43 bytes:

echo "\x47\x49\x46\x38\x39\x61\x1\x0\x1\x0\x80\x0\x0\xff\xff\xff\xff\xff";
echo "\xff\x21\xf9\x04\x1\x0a\x0\x1\x0\x2c\x0\x0\x0\x0\x1\x0\x1\x0";
echo "\x0\x2\x2\x4c\x1\x0\x3b";

Orange dot, 35 bytes:

echo "\x47\x49\x46\x38\x37\x61\x1\x0\x1\x0\x80\x0\x0\xfc\x6a\x6c\x0";
echo "\x0\x0\x2c\x0\x0\x0\x0\x1\x0\x1\x0\x0\x2\x2\x44\x1\x0\x3b";

Without color table (possibly painted as black), 26 bytes:

echo "\x47\x49\x46\x38\x39\x61\x1\x0\x1\x0\x0\xFF";
echo "\x0\x2C\x0\x0\x0\x0\x1\x0\x1\x0\x0\x2\x0\x3B";

The first two I found some time ago (in the times of timthumb vulnerability) and I don't remember the sources. The latest one I found here.

P.S.: Use for tracking purposes, not as spacers.