Question is quite simple: How to preserve file on server and in file tables, so its fid is still valid after unsetting/changing value with entity wrapper?
$ewrapper = entity_metadata_wrapper('node', $sourceNode);
unset($sourceNode->field_image[$sourceNode->language][0]);
$ewrapper->save();
Now the related file is deleted as soon as the above is called. Same happends if I use:
$ewrapper->field_image->set($newImage);
In this case I need to keep the old image.
Thanks for your help guys!