Dna. Original public domain image from Wikimedia Commons
Masks worn during experiments with plague. Manila, Philippines (1912). Original image from National Museum of Health and Medicine. Digitally enhanced by rawpixel.
Free microphone image, public domain entertainment CC0 photo.
Buying lettuce in a grocery store. Via Rawpixel
NASA GOES 12 satellite image showing earth on March 30, 2010. Original from NASA. Digitally enhanced by rawpixel.