Image width

The shortcode attribute for an image width is image_width following the documentation.
However this doesn’t do anything except getting the 200×200 image but the image is still displayed with a width of 100% in the page by the default style (<img style=”width:100%”)
One product on a page will display an blurry image over the complete width of the content.
When I use width=”200px” (from product image parameters) all goes well <img style=”width:200px” will be the output. But this is not documented in clear way and I just found it by testing and going through the image parameters.
http://magentowp.santerref.com/documentation.html#filters