I basically have respected a chronological order with this picture gallery, dividing all images into the following periods of art history:
/12 |
Antiquity | until ~300 p.C. | Neoclassicism | 1750 1830 | |
Middle Ages | 100 1400 | Romanticism | 1800 1900 | |
Renaissance | 1300 1550 | Realism | 1850 1890 | |
Mannerism | 1520 1610 | Impressionism | 1860 1910 | |
Baroque | 1580 1750 | Symbolism | 1870 1930 | |
Rococo | 1720 1780 | Modern Art | after 1900 |
All the images shown in this gallery are taken from the internet, mainly from Wikipedia.com, Web-Art.com.au and ocaiw.com.
According to those sources and the law within the USA, the European Union and Switzerland, all images are in the public domain and no longer protected by copyright.
Images by artists who died less than 70 years ago cannot be shown here due to copyright restrictions. But you find many more examples of contemporary art images with frontal nudity on specialized web sites. I have listed some of them here with direct links for your convenience.