Generate and Display Thumbnail of image ASP.Net

i  dont want thumbnail

i have grid view in my page and some image in my DB.

my images have this property width=100px hieght=100px and size=50KB

 I want show these images in grid view with width=20px and height=20px and i want   size of my images in grid view be 10KB how i can Reduce  my images size in gridview?