How to resize images using ASP.Net C#

I have images of Dimension 3008 x 1960 and 1960 x 3008. I want to resize these images. I want that if width is more than height then width=600 and height should resize in proportion of width. If height is more than width then height=600 and width should resize in proportion of height. How i will do it using ASP.Net, C#. Please suggest me.