You can achieve this by using following code:
/* Automatically set the image Title, Alt-Text, Caption & Description upon upload
--------------------------------------------------------------------------------------*/
add_action( 'add_attachment', 'my_set_image_meta_upon_image_upload' );
function my_set_image_meta_upon_image_upload( $post_ID ) {
// Check if uploaded file is an image, else do nothing
if ( wp_attachment_is_image( $post_ID ) ) {
$custom_title = date("Y-m-d"); //settings current date as title
$my_image_details = get_post( $post_ID )->post_title;
// Sanitize the title: remove hyphens, underscores & extra spaces:
$my_image_details = preg_replace( '%\s*[-_\s]+\s*%', ' ', $my_image_title );
// Sanitize the title: capitalize first letter of every word (other letters lower case):
$my_image_details = ucwords( strtolower( $my_image_title ) );
// Create an array with the image meta (Title, Caption, Description) to be updated
// Note: comment out the Excerpt/Caption or Content/Description lines if not needed
$my_image_meta = array(
'ID' => $post_ID, // Specify the image (ID) to be updated
'post_title' => $custom_title , // Set image Title to date
'post_excerpt' => $my_image_details , // Set image Caption (Excerpt) to sanitized title
'post_content' => $my_image_details , // Set image Description (Content) to sanitized title
);
// Set the image Alt-Text
update_post_meta( $post_ID, '_wp_attachment_image_alt', $my_image_title );
// Set the image meta (e.g. Title, Excerpt, Content)
wp_update_post( $my_image_meta );
}
}
Here I’m replacing image title with date and description with actual formatted title. This action will run every time you upload a new image.