static File loadBinarySnippet(S snippetID) ctex {
  long id = parseSnippetID(snippetID);
  if (isImageServerSnippet(id)) ret loadImageAsFile(id);
  File f = DiskSnippetCache_getLibrary(id);
  if (fileSize(f) == 0)
    f = loadDataSnippetToFile(snippetID);
  return f;
}