How to increase image size in Data Grid Extension widget?

Hi ,

I have a scenario where i have to show buttons and hyperlink in a grid. To achieve this task i implemented Data Grid Extension . For hyperlink field i wanted to give caption along with image , I am able to give image to the field but unable to increase the size of the image. Though i am increasing the size of image and adding it to the images folder while i am adding it to the Data Grid Extension , i don't know for what reason the image size is not increasing.Can anyone suggest me how to increase the image size in Data Grid Extension widget.

Thanks in Advance!