Can you change the default size of the "add image" window (thumbnail browser)?

Hi - I have searched but am unable to find any info on this one.

Image assist creates a new browser window to enable adding of an image via the thumbnail browser. This window is approx. 600x400. If I use views to show more thumbnails in the img_assist_browser view the browser still appears at that size (with scrollbars), therefore it needs to be resized to see all the thumbnails (as per the attached screenshot).

Is there a way to change the setting of the new window that is generated. I looked in all the .js files and the css but couldn't see where it could be overridden (that said, I am a relative newbie at this...)

Thanks for any help.

Robert in Oz