I have just hosted a WordPress plugin on WordPress.org.
It includes a readme.txt file (that passes the validator) and a screenshot-1.png file.
(Check them for yourself at: http://svn.wp-plugins.org/compact-monthly-archive-widget/tags/1.0/)
However, when I view the corresponding page ( http://wordpress.org/extend/plugins/compact-monthly-archive-widget/screenshots/ ), I get 404 errors for the screenshot.
I suspect a silly newbie mistakes, but I haven't been able to see any errors and I can't find any similar complaints.
Any suggestions?