A significant breaking change has been introduced: the imageUrl property within the CommentSnippet schema is now explicitly readOnly. This means any attempts to provide or modify an image URL when creating or updating comments will fail. The API will now only return this property if a comment contains an image or GIF, served as a signed link with a six-hour TTL. Developers must update their applications to reflect this change.
Separately, various media upload methods across the API have seen updates to their accepted MIME types. Methods like captions.insert, channelBanners.insert, playlistImages.insert, thumbnails.set, videos.insert, and watermarks.set now generally offer more flexibility in the Content-Type headers they accept, often including application/octet-stream or a broader */*.
