I've been wrestling with a certain kind of Netscape fluke on several pages for quite some time.
The oddity shows up when I have an image that is sliced up beyond one vertical strip -- and then held together either with table cells or just coded inline using <BR> tags.
Even though many different code configurations will give a perfectly matched up image in MISE, Netscape often insists on adding an extra one pixel gap between the last two horizontal strips.
Sometimes I can fix this by eliminating all hard returns in the code -- seems that Netscape doesn't always ignore returns and can mistake them for a <BR>.
Sometimes I can eliminate the table and just list all the pieces inline with appropriate breaks. And sometimes the reverse needs to happen -- inline pieces show the gap but a table will hold the pieces together without a seam.
And in one case, I can't think of anymore options, so Netscape users get the gap and Explorer users see the seamless image.
Wrestle is the word. I am trying to figure out how I solved it eventually, but I think it had something to do with setting the height of the cell to the height of the image. If that doesn't work, get back here and I will have a look at the site where it happened tomorrow.
What are you using to slice and dice your graphics? Or are they separate graphics that you want to appear as one? We use ImageReady to slice and dice. It creates a table that seems to work very well in both NS and IE. The only way we have been able to take separate graphics and merge them into what appears to be one graphic is to use nested tables with very careful attention to cell spacing and cell padding and borders. I'll check the couple of places we did that and see if there is anything special to the table layout.