SSRS 2005: how to use an external image in a texbox by an expression

Hi,

I want to use an external image in textbox value field by expression. I am trying to do that by the below expression:

= IIF (Fields!abc.value = "yellow", Yellow_Status.png, "")But getting the Error: The value expression for the textBox12 contains an error. The Image1 Yellow_Status is not declared. Please help me.