read tuts

dude, you're so cool not answering his question.

@OP
Could you please rephrase or explain what you mean by "signatures that have been split?"
try posting an example.

like this

Make a signature, then make a new layer above and go to Image -> apply image. Hide ALL layers underneath, then use the rectangular marquee tool to select and delete between "parts" of the signature. If you want a border, go to Layer Settings and select Stroke.

Hope this helped.

your also going to probably need to save the file as a .png