These images shipped with the WeeWX Phenology Extension are believed to be in the public domain:

• Ebraminio. "North Pointer." 7 Nov. 2013. Wikimedia Commons. 17 Jan. 2021 <https://commons.wikimedia.org/wiki/File:North_Pointer.svg>.
• Hillebrand, Steve. "Mexican Poppies and Mountains." 27 Feb. 2013. Wikimedia Commons. Eschscholzia californica ssp. mexicana. 19 Jan. 2021 <https://commons.wikimedia.org/wiki/File:Mexican_poppies_and_mountains.jpg>.
• United States. Dept. of Agriculture. "Corn." Illus. 1 Aug. 2019. 19 Jan. 2021 <https://www.usda.gov/media/blog/2019/07/29/corn-americas-largest-crop-2019>.
• United States. Dept. of Commerce. National Oceanic and Atmospheric Administration (NOAA). NESDIS. "Cirrus Clouds." Illus. SciJinks. 19 Jan. 2021 <https://scijinks.gov/review/clouds/cirrus.jpg>.
• United States. Dept. of Energy. Fermi National Accelerator Laboratory. "The Woods in Winter." Illus. By Marty Murphy. 3 Jan. 2017. 19 Jan. 2021 <https://news.fnal.gov/2017/01/the-woods-in-winter/>.
• United States. Dept. of the Interior. National Park Service. "Air Quality Webcam Archives: Grand Teton National Park." Aug. 2011 — Jan. 2021. Still 1.3MB frames from a fixed location on the quarter hour at all seasons. 18 Jan. 2021 <https://npgallery.nps.gov/AirWebCams/grte>.
• United States. Dept. of the Interior. National Park Service. "Wheat." Illus. Cedar Creek and Belle Grove. 5 June 2013. 19 Jan. 2021 <https://climate.nasa.gov/news/954/climate-forecasts-shown-to-warn-of-crop-failures/>.