c# OnMouseEnter() - Mouse on a specefic image.

Hello,first time to ask question here.
I’ve just started to experience Unity3D yesterday,and yeah it’s AMAZINGLY GREAT!!!

I worked on a project in “C++ & SDL” before,but anyway. Though C# is very different from C++,I tried very hard to be familiar with C#. Below is my goal.

“When my mouse is over a image,it’ll change into another image.” (Just like an option button.)

In SDL,I do this by detecting if my mouse moves into the area of the image(Coordinate x and y ) then I change the image.

But I know that in Unity3D I can do that by using OnMouseEnter(). Unfortunately I have no idea how I’m gonna do that exactly.

I don’t know if I should use the sprite or renderer as a object.

It would be great if anyone can help me with this,a pseudo code would be nice. Thanks!

yu dont need to do any of that, read this link text