Change inches to pixels.

Make it 400x150.

Minimum size is : 300 pixels (Width) by 100 pixelds (Height).
Maximum size is : 400 pixels (Width) by 150 pixels (Height).
Maximum Sig size is: 70 kb's

That's the basics you should know.

don't, these huge sigs are awful

edit: as for the screen u posted:
change 'inches' to 'pixels' and make width up to 400, height up to 150 (but as i said, i wouldn't advise maximum, but if u make it lower than 300x100 then the sig might be illegible)
leave the rest, click 'Ok'

This post was edited by Godless_hc on May 9 2009 11:09am

Man, if you can't figure that out, you're really gonna struggle with this.