An asterisk doesn’t always mean a pointer. I believe the **__cdecl *FPreviewRenderPluginModule:: means that it must be delegated to a method from the FPreviewRenderPluginModule namespace. So that means __cdecl just ensures the namespace is a class declaration.
The first const means the return type has to be marked as const and the last const means the delegate function must be marked as const.
The (void) in that position just means there’s no input parameters to go into the function.
I’m pretty sure Image_Raw(), Image_Lambda(), Image_UObject(), etc. are all generated methods since they’re not in the source. But that also makes it hard to see what they’re doing, since I can’t find where the relevant code is.