WordPress can be customized a lot if you are ready to get your hands dirty with the functions.php file. This is useful to unclutter the interface for your less computer-savvy users, and basically, to reduce the complexity of their experience as much as possible (less complexity, less chance to make errors and experiment frustration).

One of the interfaces they’ll probably use a lot is the one that appears when they want to add an image or media file: the “Add an attachment” screen.

Add This function to your theme’s functions.php to hide all fields that you want to hide to your “author” users

function remove_attachment_fields($form_fields) {
if ( substr( $post->post_mime_type, 0, 5 ) == ‘image’) {
   		$form_fields['image_description']['input'] = 'hidden';
	if (current_user_can('author')){
// Alternative text
   	$form_fields['image_alt']['value'] = '';
        $form_fields['image_alt']['input'] = 'hidden';
// Description
        $form_fields['post_excerpt']['value'] = '';
        $form_fields['post_excerpt']['input'] = 'hidden'; 
// Title      
       $form_fields['post_title']['value'] = '';
        $form_fields['post_title']['input'] = 'hidden';
        $form_fields['post_content']['value'] = '';
        $form_fields['post_content']['input'] = 'hidden';
// Url associated to the image's click behaviour
        $form_fields['url']['value'] = '';
        $form_fields['url']['input'] = 'hidden';
// image alignment
        $form_fields['align']['value'] = 'aligncenter';
        $form_fields['align']['input'] = 'hidden';
// image size that will be injected inside your post content if you insert it
        $form_fields['image-size']['value'] = 'thumbnail';
        $form_fields['image-size']['input'] = 'hidden';
        $form_fields['image-caption']['value'] = 'caption';
        $form_fields['image-caption']['input'] = 'hidden';
        $form_fields['buttons']['input'] = 'hidden';
        return $form_fields;
	}
}
}
add_filter('attachment_fields_to_edit','remove_attachment_fields', 15, 2);