I have a model with the field "image", which is a simple VARCHAR with the image name. My extbase extension is called ophi_insta and the model is named entry. When I save the image, it is uploaded to uploads/tx_ophiinsta/ and the filename (without the path!) is saved to the database column "image". What I want is to show the thumbnail of this image beneath the model title in the backend list view. Interestingly enough, this is quite easy: in ext_tables, where $TCA for the model is defined, the following must be added: 'thumbnail' => 'image'
$TCA['tx_ophiinsta_domain_model_entry'] = array( 'ctrl' => array( .... 'thumbnail' => 'image', .... ), );
I am honestly surprised that this is working.