# Imageio environment variables

This page lists the environment variables that imageio uses. You can set these to control some of imageio’s behavior. Each operating system has its own way for setting environment variables, but to set a variable for the current Python process use `os.environ['IMAGEIO_VAR_NAME'] = 'value'`.

- `IMAGEIO_NO_INTERNET`: If this value is “1”, “yes”, or “true” (case insensitive), makes imageio not use the internet connection to retrieve files (like libraries or sample data). Some plugins (e.g. freeimage and ffmpeg) will try to use the system version in this case.

- `IMAGEIO_FFMPEG_EXE`: Set the path to the ffmpeg executable. Set to simply “ffmpeg” to use your system ffmpeg executable. If not given, will prompt the user to download the ffmpeg exe that imageio provides.

- `IMAGEIO_AVBIN_LIB`: Set the path to the avbin library. If not given, will prompt the user to download the avbin library that imageio provides.

- `IMAGEIO_FREEIMAGE_LIB`: Set the path to the freeimage library. If not given, will prompt user to download the freeimage library.

- `IMAGEIO_FORMAT_ORDER`: Determine format preference. E.g. setting this to `"TIFF, -FI"` will prefer the FreeImage plugin over the Pillow plugin, but still prefer TIFF over that. Also see the `formats.sort()` method.

- `IMAGEIO_USERDIR`: Set the path to the default user directory. If not given, imageio will try `~` and if that’s not available `/var/tmp`.