This first table is the simple test case. Colspan confuses the width allocation when there is an image in the colspanned row.

foo | bar

This second table is the same as the first, minus the second 'colspan=2' row. Widths are now correct.

foo | bar

An observation: Note that as the image-width approaches the table-width, the two columns approach equal width (error increases). Conversely, below some threshold image-width (which is about 390px or 30px less than the TD WIDTH=420), the error is (apparently) zero.

Here the <img width=600>

foo | bar

Here the <img width=400> (error is almost zero).

foo (single row table) | bar (single row table)

foo | bar

I tested the above with M4 and May01 build for win95. (The above examples assume that images load normally -- N.B. for May01 the images initially load, and the width error is visually apparent, but then the images get replaced by their ALT text, and the width error is no longer present -- this is, of course, a different issue/bug.)