>I am not able to correct my problem. I try your code but i get error.
>MY field name is "path" Where the all picture path is saved. I put the code only in file like "studnet.path". Student is the my table name and the path is the field name where is path of the picture is stored. thanks

Where is the name of the picture stored or come from?
What did you put into Field Expression?
What did you put into Pint When?
What are values stored in the "studnet.path" filed? Provide a few samples, please.