Does not work

Hello,
After I have installed this plugin, I added an image to a category, and included the
<?php cat_image(<term_id>); ?>
code in the header loop.
However, that just made that the page stopped loading completely, some kind of error, and it makes the page blank.

I want to show images on the top of the listings of recent articles by category.
So, for instance, I have a category thats named “alla”, and that should show her photo on the top. I can’t seem to make that work no matter what i try.

Any help?
Thank you

http://ww.wp.xz.cn/plugins/wp-category-images/