As far as I know, there is no direct counterpart to an ImageField.
What you can do is to use an AbstractObjectColumn (or any other) and overwrite the execDecorateCell method.
In this method you set the icon id, i.e. cell.setIconId(imageId);
In Swing, the icon is retrieved by calling getIcon in the AbstractSwingEnvironment. Thus you can overwrite the getIcon method in your SwingEnvironment and handle the Icon retrieval there.
To somehow have a proper solution, you can create a cache for your images (e.g. in the Activator class). You explicitly cache the image in the execDecorateMethod (before calling cell.setIconId), and retrieve it from cache in getIcon of the SwingEnvironment.
Actually it should not be necessary to override any method in the swing environment. Just put the icon in the recources/icons folder of your client plugin and it should automatically be loaded and even cached.
I will create an example application for you. It should work with any supported GUI framework. Just the part of overwriting the getIcon method needs to be done in all environments, the other code does not depend on a specific GUI.
This may be a limitation of the swt and therefore rap table, but I don't know really. Have you tried to use html content? If you are using Scout 3.8.0 you can refer to registered images with cid:.
Example (not tested):
<img width="16" height="16" src="cid:iconId"/>
As far as I know this only works with the rap ui so far.
BTW: Even though loading dynamic images by overriding IRwtEnvironment#getIcon() works, it looks a little complicated to me. It should be far easier by implementing a custom IIconProviderService which is able to load the images dynamically.