Bo, the Obama's family pet, plays in the snow during a blizzard on the south grounds of the White House, Feb. 10, 2010. https://www.rawpixel.com/image/4048851/photo-image-public-domain-dog-snowFree Image from public domain license
Victoria crowned pigeon, bird photography. Free public domain CC0 image. https://www.rawpixel.com/image/6035465/photo-image-public-domain-nature-birdFree Image from public domain license
A close-up of a dandelion in Romania. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3284184/free-photo-image-aesthetic-animal-apiaceaeFree Image from public domain license
Free deer with big horns in forest image, public domain animal CC0 photo. https://www.rawpixel.com/image/5921594/photo-image-public-domain-nature-waterFree Image from public domain license
Purple Gallinule , NPSPhoto, R. Cammauf. Original public domain image from Flickr https://www.rawpixel.com/image/4033790/photo-image-flower-plant-birdFree Image from public domain license
Mormon village of Mona, below the foothills of Nebo Peak, Wahsatch Range. by William H Bell https://www.rawpixel.com/image/14288266/photo-image-horse-art-animalFree Image from public domain license
Big rattle snake, wildlife photo. Original public domain image from Flickr https://www.rawpixel.com/image/3399604/free-photo-image-rattlesnake-animal-cc0Free Image from public domain license
Barn SwallowPhoto by Courtney Celley/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4029038/photo-image-wood-bird-natureFree Image from public domain license
Free black labrador retriever dog's face side view image, public domain animal CC0 photo. https://www.rawpixel.com/image/5913851/image-background-face-public-domainFree Image from public domain license
Multi-color maple leafPhoto by Joanna Gilkeson/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4029245/photo-image-tree-plant-leafFree Image from public domain license
Skeleton of thorax, pelvis, arms and legs: six figures. Engraving by Francesco Bartolozzi, 1796, after Leonardo da Vinci. https://www.rawpixel.com/image/13968880/image-paper-cartoon-personFree Image from public domain license
Free rough knob-tailed gecko image, public domain animal CC0 photo. https://www.rawpixel.com/image/5921866/photo-image-background-white-public-domainFree Image from public domain license
Ausable Chasm, from Head of Birmingham Falls. by S R Stoddard https://www.rawpixel.com/image/14298748/ausable-chasm-from-head-birmingham-falls-stoddardFree Image from public domain license
Red-tailed hawk perched above the Gardner River (Buteo jamaicensis)by Jacob W. Frank. Original public domain image from… https://www.rawpixel.com/image/4038529/photo-image-trees-bird-landscapeFree Image from public domain license
Monarch caterpillar on common milkweedMonarch caterpillars are busy chowing down on milkweed leaves and growing quickly.… https://www.rawpixel.com/image/4028304/photo-image-plant-leaf-butterflyFree Image from public domain license
Four women and two men swimming near bathing machines. Wood engraving. https://www.rawpixel.com/image/13971544/four-women-and-two-men-swimming-near-bathing-machines-wood-engravingFree Image from public domain license
Western Painted Turtle SunningPhoto by Courtney Celley/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4028830/photo-image-nature-animalFree Image from public domain license
Men and Pack Horses in Forest Clearing by Louis Fleckenstein https://www.rawpixel.com/image/14281671/men-and-pack-horses-forest-clearing-louis-fleckensteinFree Image from public domain license
Green tree frogA green tree frog was spotted during a National Public Lands Day event at Cave Run Lake, Morehead, Ky. Green… https://www.rawpixel.com/image/4036780/photo-image-nature-animal-public-domainFree Image from public domain license
Internal view of the human brain, "The functions of the brain", Ferrier 1876 https://www.rawpixel.com/image/14003481/internal-view-the-human-brain-the-functions-the-brain-ferrier-1876Free Image from public domain license