to manege small portal -full WYSIWYG (includind code) -option to open new category (on the main menu) -tags option -preview image option to the aticles
for exmple look at: http://www.bbc.co.uk/ or every news website you have picture in the homepage before you click on the article
Have a look at CMS Made Simple. It's got less bloat than many others like Joomla/Nuke/etc. but is still pretty fully featured.
There are several CMS - wordpress, tinyportal, and drupal are some of the first ones that come to mind. There is no reason to install joomla - that is like putting a "please hack my site" flashing sign on your website. Joomla is popular, but it is also one of the least secure CMSs on the market.
Wordpress is probably most customizable than any other. As you see people here will suggest your Wordpress.
I'll vote for WordPress too. It's very easy to use as a CMS instead of a blog, just use the pages instead of posts. There are so many themes available too, so finding one that will display images like you want is easy. Just search for a 'magazine' style theme, they usually have that feature.
~kev~ interested to know more details on the security concerns for joomla (vs. drupal). we are trying to evaluate drupal vs. joomla - do you have any more information to share?
I often read of joomla being hacked easily but the same can be said for other popular scripts, some forum scripts get hacked more than others because of them being popular. Anything can be hacked.
I'd say Wordpress as long as you keep it up to date, which is easy now thanks to the included automatic update system.