think it has to do with "fortune city" they may be over riding the img and sending thier link thur
get a account at www.sigcenter.com/
it free post your sig there take about 4-8hr's it be up
there is a drawback sig can only be 100kb so make it .gif
if its going to be too big this way it be smaller in size,
they let you post up your sig there as in artwork a lot of people use them.
i use geocities drawback they don't let people make links to thier IMG at all thats why i use
.jpg or jepg some times are way too large
but format it .gif same size but a bet small
"sigcenter"