Views load the whole entity even though they only need 3 fields I am using Views to fetch the 3 fields of a specific entity. However, this leads to the view to make a full load of the entity and all the images included in it, even though they are not displayed. This leads to loading 20 images per entity instead of 1!.
How can I hook into the process and modify this. I tried almost all view's and entity's hooks but nothing seems to have an effect. Any ideas?
Are these custom entities or from a module? If they are custom you could try to override the 'query' or 'load' function in the entity controller class (defined in hook_entity_info() ). If it is from a contributed module, there isn't anything you can do without altering the module code.

Also please note that the actual images are only loaded when the browser requests them over http via an  tag, the entity loads the fields over SQL. Agreed, this creates some overhead. But I guess you would hardly notice the difference when a few fields less are loaded.