The plugin covers basic functionality. However, as a developer, I sometimes need to do custom tasks that aren't covered by the plugin (for example, I wrote WP CLI wrapper around the plugin). Compression is currently triggered during various events, but it seems there's no easy way to execute it manually from standalone PHP code. I propose to add Tiny_Plugin::compress(). Ideally, for consistency reasons, all other compression methods should rely on and call it:
Tiny_Plugin::compress_on_upload(),
Tiny_Plugin::compress_image_from_library(),
Tiny_Plugin::compress_image_for_bulk()
I can submit PR if this feature request is accepted.