[Lazarus] Customizing image preview in TOpenPictureDialog
in order to show animated gif, png and webp images, I subclassed the
TOpenPictureDialog and overrode the ClearPreview and UpdatePreview methods.
Those methods are called but the picture shown isn't the one I try to
show in my overridden UpdatePreview (e.g. I load a different picture
that the one selected but the dialog happily shows the selected one, or
e.g.2 I added support for webp images and under windows they don't show,
they do with qt5 but they show also with the standard control).
What's the correct method to customize the preview?