Media-data (category)

embed_oembed_html

Allows you to change cached oEmbed HTML when it is displayed.

getimagesize_mimes_to_exts

Allows you to add an image MIME type and its corresponding file extension.

image_editor_output_format

Allows changing the format in which the WordPress image editor saves processed images and generated sizes.

manage_media_columns

Allows you to change the list of registered columns in the Media table.

oembed_dataparse

Allows you to change the content (HTML) generated when URLs supported by WordPress's oEmbed format are embedded. The change occurs before caching.

upload_mimes

Allows adding/removing file types that can be uploaded to the site (file MIME types allowed for upload).

wp_editor_set_quality

Allows changing the default image compression quality based on its MIME type and dimensions.

wp_insert_attachment_data

Allows you to modify attachment (Media Library file) data before it is updated or added to the database.