The symbol folder contains all symbols in four versions: PNG without frame, PNG with frame, JPG without frame and JPG with frame. If the language setting is German, these 4 versions are displayed in the search window. With other language settings (English, French, Italian, Dutch, Swedish, Spanish) only 2 versions are displayed: PNG without frame, JPG without frame.
If you do not want to use all versions, e.g. to save space on the hard disk, you can remove parts from the symbol folder.
For example, if you remove the Symbols_JPG folder with the subfolders JPG_with_frame and JPG_without_frame, only the PNG symbols without and with frames will be available. If you also remove the subfolder PNG_with_frame, only the PNG symbols without frames are available: