I want to add an image to pdf file. I am using prince method to generate pdf file in my ruby on rails application. in my rhtml file, i have used image_tag to display image. and image path is stored in session which is displayed perfectly. but in pdf file I don't get an image. so plz help.

Check if you get any errors in the Prince log file. Can you also see the HTML that is being given to Prince? That will make it easier to see what image path is being used, and whether it is something that Prince can access.