Image Field, URL value assigned using script

Image Field, URL value assigned using script

Hi, 

I have a form, where I have an Image field. I want to run a script to assign each record a URL value to the image field. The issue is that the script seems to do nothing, i.e. the URL string is not written into the field.

below the type of script I am talking about, which produces no change in the Image field... thanks for your support...

for each F in Fotos

{
F.Image="URL";
}