iReport Report with oid postgresql image

I am putting together a report using iReport Designer, when I click on "preview" the report is displayed correctly. Now I want to display some images that are in the (PostgreSQL) database, the images are of type "oid" and my query is also done inside the iReport Designer itself. I found some examples passing the image via parameter through a class in a java application, but this is not my case. I want to display the image that is in the database in my report. Does anyone know how to do this? Thankful