I am using Atahualpa 3.5.3 in WordPress 3.5.3. I imported 1000 width x 160 height pixel images for the rotating header. I created soft edges on right and left side. Left side by the logo is fine and it is the soft edge that I created in my images. But, it seems that the theme randomly truncates the image on the right hand side... and I get a hard edge, even though the right edge of my image that I loaded has soft edge. How can I make the theme use the header image as excactly the way I uploaded? What is the header image width that I need to use?

how wide is your page contained defined as?
what is your 'ato->NEW Header Image->Header Image: Alignment' option set to?