Menu -> File -> New

• Width and Height
•
The width and height of your future image (up to 30000x30000).  In the listbox you may select 
most widespread sizes. "Square" checkbox allows to input only one size with 
copying content to another.
 
• Seamless
•
Checkbox for choice between seamless or standart mode.
• Background
•
Defines background of an initial image.  If you choose "Blank" 
than
starting background will become black. If you choose "File" than you
may set  an image file as initial background. Image sizes will be equals the 
size of an image file
(up to 30000x30000).