piatkow - 12:47 pm on Jul 2, 2009 (gmt 0)

The alt attribute is where the alternate text should reside. I haven't tested any screen readers myself and an overly brief check with Google wasn't especially helpful with references to reports of tests involving linked images and images with both alt and title attributes defined.

I am afraid that to debug a problem like this you need to understand the code that Publisher produces. If I was in your position I would first hand code a simple web page with just a picture and test to determine if the problem was with the reader or with the code generation. Actually you should be able to pick up sufficient html to do that amount of hand coding in a couple of hours.