Theme Borders

The theme I am using ( Elegant Grundge ) gives all images bigger than 25*25 an automatic border which looks like such: http://i141.photobucket.com/albums/r51/jazzcash/Wordpress/Border.png

I want my images to have no border and to look like this: http://i141.photobucket.com/albums/r51/jazzcash/Wordpress/Noborder.png

However whether this option is ticked or not, my images have this automatic border applied anyway.

Can someone tell me how I can remove this border from all my images please?