Change width to 100% rather than exact px

Hi,

I'm trying to theme the images created using this module, but the default tagging puts:

The width and height are automatically put in by the module and correspond to the original upload size.

This is overriding my CSS attempts to make the width percent based and the height to scale automatically because the width and height are added AFTER the CSS has been read and applied.

I can go through the .module file and remove this, but that doesn't seem like a best practice. Is there a better way to achieve this? It should be pretty simple.