As far as I can see from the code it's pretty much theme dependant. A regular TR tag is used and the inclusion of the image is outside of any DIV CLASS="..." scope. The only class it indirectly belongs to, due to it's cell, as far as i can see, is "odd", which doesn't influence the width.

Maybe you can edit your theme's style.css and add a class that does what the "odd" class does plus defines a width. Or assign an id to the cell and define whatever you want in there.

Now I am relatively new to XOOPS so I'm not 100% sure it'll work but judging the code the solution should be in that area. E.g. the style.css and the newbb_thread.html files. Feel free to correct me staff

EDIT: excuse my double post. accidents happen.