450x150
there is absolutely no need for anything bigger than that.
and ive been a sig maker for over a year.
EDIT-
also some other suggestions and questions
this signature size limit would be for the ENTIRE SIGNATURE BOX. Not just 1 image.
It would include all the text lines and everything? If not i think it should.
Also you might want to set a maximum size limit, such as 60kb.
Any actual sig maker can get a great quality signature under 30kb let alone 60kb.
And i dont think you want to discourage dial-up users from comming here with huge 200kb signatures.
Just my opinion, and suggestion.
