A data-aware image field can be added as easily as a line-edit field. Simply choose the image object (the Mona Lisa) and position it anywhere in your form. Set the column (if the column type is 'binarycolumn' images will be stored inside the table (not recommended!), otherwise (recommended) it will store the path and the name in the column ).
You should not store images inside the database. Instead only store the file location and the image name within the database. This way, memory management is much better.
Let's say your images are located in '/opt/images'. Then set 'Image path' in the property editor to this value. Set 'Field' to a fieldname in your table that contains the file names. That's all. During viewmode you can set the image when you click the right mouse button on the image field and select 'Load image'.
If you want to display a non-dataaware image field, you can set a permanent image in the property editor position 'Local image'.