It looks like the edges of your slices aren't exactly aligned (eg. there's a one pixel gap between them). Can you check for this by zooming in on the slices around the problem areas?
Adobe Firworks-Line through mapped image
Question
I have a problem with Adobe Fireworks. I was mapping some stuff via Polygon Slice/Hotspot tool and this white lines appeared cross-image. Any solutions, how to retouch/delete them?
Solution
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