How do I add an image to a dataset?

This is a C#/Silverlight question although I am trying to emulate what I see in Excel.

In the screen snapsot below, there is an excel file that has little arrow indicators inside the cells of one column. First of all, I do not know how even this can be done. For starters, that would be a good thing to learn. But I need to emulate this in a C# / Silverlight app. How would I put little graphics like this into a dataset/datagrid?