Well here's 2 tutorials I made awhile ago...to do this you can use Photoshop of version 7+
The tutorial will tell you how to make a that cool rainbow effect and how to blend images.
If you have any other questions or whatever about how to make siggies please feel free to ask and I will try and put up a new tutorial relating to your question!!
Here you go! Hope that helps!!
If u want to know how to make Animated Siggies go here: https://www.indiaforums.com/forum/avatar-and-signatures-shop/104448/tutorial-on-how-to-make-animated-siggies
And check out my signiture page here:
https://www.india-forums.com//forum/avatar-and-signatures-shop/95853/smilingstars-signiture-page
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