What a lot of people do is copy the photobucket URL over to some place like TinyURL and then include that in your image code. That shortens the URL enough that you should be able to add more blinkies to your siggy.
it counts characters in the actual URLs that you are including..every character stroke. Try renaming your blinkies to shorter names, or you can even use www.tinyurl.com too to shorten the name of the blinkie and that should do it.