Smallest Base64 image

gistfile1.txt

data:image/gif;base64,R0lGODlhAQABAAAAACw=

Just try this service: link

Tried the tool in the link with the bare minimum settings of 1, 1, 1 and the result was:

iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAEElEQVR4nGI6MCsWEAAA//8D3QG6Bc6D/gAAAABJRU5ErkJggg==
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAEElEQVR4nGI6MCsWEAAA//8D3QG6Bc6D/gAAAABJRU5ErkJggg==

Nice tool.

Smallest(that I know) Base64 images: Black, White and Transparent(Clear)

1 pixel good for PHPs and JavaScripts because don't have any // or ++ and other symbols that can interfere(also small, only Black PNGs for What I know ):
PNG Black data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQImWNgYGAAAAAEAAGjChXjAAAAAElFTkSuQmCC
PNG Black data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVQYGWNgYGD4DwABBAEAqXIB5QAAAABJRU5ErkJggg

Normal, No Code Amicable:

GIF White data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs (Smallest that I know)

GIF Black data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAAAAAAALAAAAAABAAEAAAICRAEAOw

GIF Clear data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw

PNG White data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQImWP4//8/AAX+Av5Y8msOAAAAAElFTkSuQmCC

PNG Black data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAAAAAAALAAAAAABAAEAAAICRAEAOw

PNG Clear
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAAQSURBVHjaYvj//z8DQIABAAj8Av7bok0WAAAAAElFTkSuQmCC

I hope this helps.
Best regards,
Ramón