make product catalog image clickable and custom its size

Hi team,

I have two questions regarding the product catalog image in my shop – http://www.addictedtodesigns.com

1. I am displaying external products only. For now, users can only click on the products name to open a new page. I would like to make the picture for external products clickable too with the same URL used for the product name. Possible?

2. I have many different product categories. Can I custom the product size per category? some need to be higher, some widther. Possible?

Thanks for your help,
Patrick