Neither link is meant to give a comprehensive list of accepted extensions/types, but Graphics.GetGraphicClassForFileExtension can give a class ...
Thank you for the example. I see that lots of formats are
actually supported.
And if this support has been added time ago, and well tested, then why not to update the documentation?
What I am trying to say, in most of mature systems there also some features appear before they get documented. But they are treated as "undocumented features", that are not recommended for use, especially for production use, until they are released and documented.
From what you are saying I see that this approach does not apply to FPC/Lazarus. Then how to be sure that some new cool feature I use today, will not change tomorrow, and something will stop compile or work?