PNG Files
Portable Network Graphics

PNG is a data directory which contains examples of files in the PNG or "Portable Network Graphics" file format.

PNG files can do a good job of showing both line graphics (what PostScript files do best), and bit-mapped graphics (which are commonly handled by JPEG or GIF files). Most web browsers support the PNG format, which makes it easy to include pictures directly in a web page.

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

PNG_CRC, a C++ program which computes the CRC (cyclic redundancy checksum) for a PNG graphics file (or any other file, for that matter);

Reference:

1. The PNG Home Page at http://www.libpng.org./pub/png/
2. David Duce, editor,
   Portable Network Graphics (PNG) Specification, Second Edition.
   Technical Report REC-PNG-20031110,
   World Wide Web Consortium, 2003.
3. Greg Roelofs,
   PNG: The Definitive Guide,
   O'Reilly, 1999,
   ISBN: 1-56592-542-4,
   LC: T385.R588.

Sample Files:

• ajou_logo.png, a logo for Ajou University, in Suwon, Korea;
• all_gray.png, a tiny monochrome image;
• apollonian_gasket.png, an image of the fractal shape known as the Apollonian gasket.
• aquarium.png, a model of Greg Hood's new surf aquarium;
• archimedes_after.png, a page of the Archimedes palimpsest after imaging.
• archimedes_before.png, a page of the Archimedes palimpsest before imaging.
• auburn_logo.png, a sports logo for Auburn University.
• baboon.png, a grayscale image of a baboon;
• balloons_noisy.png, a noisy image of a couple with balloons.
• bar.png;
• bell_206.png, the Bell 206 helicopter;
• bell_v22.png, the Boeing-Bell V22 Osprey;
• blackbuck.png, an image of a deer;
• bmp_08.png, a monochrome image derived from a BMP file;
• bmp_24.png, a three-color image derived from a BMP file;
• brain.png, a black and white MRI image of the brain;
• bubble_chamber.png, an image from a bubble chamber showing particle creation and collisions.
• buffalo.png, an image of several buffalo.
• casablanca.png, a still from the movie "Casablanca";
• cat.png, a simple line drawing of a cat;
• charlie.png, a photograph of Charlie the dog;
• cheetah_running.png, a running cheetah.
• chest_xray.png, a chest X-ray image.
• clemson_logo.png, a logo for Clemson University;
• clemson_logo_sports.png, a sports logo for Clemson University;
• coins.png, an image of coins;
• dewey_defeats_truman.png, a grayscale image, Harry Truman has a laugh.
• dla.png, an image of a structure created by diffusion-limited aggregation.
• dog_shadow.png, illustrates the determination of the shadow of a dog;
• dots.png, dots all I can say;
• dragon.png, a cartoon of a dragon;
• durer.png, Melencolia I, by Albrecht Duerer;
• emory_logo.png, a sports logo for Emory University;
• eniac.png, an image of the ENIAC computer.
• f14.png, an image of the F14 fighter jet;
• feep.png, an image of "FEEP".
• fool.png, a black and white (not grayscale!) screenshot from "The Fool's Errand";
• football_seal.png, the seal of Football Stadium University;
• fouroclocks.png, an image of four o'clock flowers.
• fractal_tree.png, a photograph of a tree suggesting a fractal structure.
• fsu_logo.png, a logo for Florida State University;
• fsu_sports_logo.png, a sports logo for Florida State University;
• glassware_noisy.png, a noisy grayscale image of glassware.
• greenland_grid_velo.png, a contour plot of ice sheet velocity over Greenland;
• harvard_mark.png, a picture of the Mark computer at Harvard.
• heawood.png, an image of the Heawood graph, converted from a GRF file to an EPS file by GRF_TO_EPS, converted to a PNG file by ImageMagick Convert.
• humanoid_tri.png, a 2D 'snapshot' of a 3D humanoid shape made with 96 triangular faces.
• icam_logo.png, a logo for the Interdisciplinary Center for Applied Mathematics at Virginia Tech;
• idataplex.png, an image of IBM's iDataplex computing system;
• knightstour.png, an image of the Knight's Tour graph, converted from a GRF file to an EPS file by GRF_TO_EPS, converted to a PNG file by ImageMagick Convert.
• lena.png, a 512x512 grayscale image.
• lena_noisy.png, a "noisy" version of the lena image.
• lizard.png, an image of a lizard.
• lizard_noisy.png, a noisy image of lizard.
• prototein.png, a schematic of a simple model of protein folding.
• math_emporium.png, the layout of Virginia Tech's Math Emporium.
• maze3.png, a maze;
• milking.png, a grayscale image of a cow being milked.
• mona_lisa.png, a black and white image of the Mona Lisa;
• mountain.png, a black and white image of a mountain (looks like the Alps).
• move1.png, an optical illusion in which dots seem to move;
• move2.png, an optical illusion in which dots seem to move;
• move3.png, an optical illusion in which dots seem to move;
• mushroom_shadow.png, an illustration of the problem of computing the shadow of an object (in this case, a mushroom).
• noise_salt_and_pepper.png, an image which illustrates "salt and pepper" noise.
• northatlantic_phys.png, a topographic map of the area around the North Atlantic.
• pengbrew.png, a penguin with a beer;
• petersen.png, an image of the Petersen graph, converted from a GRF file to an EPS file by GRF_TO_EPS, converted to a PNG file by ImageMagick Convert.
• pioneers.png, a couple of boys dressed up as pioneers.
• pitt_logo.png, a logo for the University of Pittsburgh.
• pitt_logo_sports.png, a sports logo for the University of Pittsburgh.
• pngnow.png;
• pngtest.png, a picture of the stylized letters "PNG";
• promenade.png, a grayscale image of a group of people walking down a tree-lined path.
• prototein.png, a schematic of a simple model of protein folding.
• roi_14.png, a 507 wide by 505 high image of an MRI, the 14th in a sequence.
• sc_logo.png, a logo for the Department of Scientific Computing at Florida State University;
• scs_logo.png, the logo for the School of Computational Science at Florida State University (since renamed the Department of Scientific Computing).
• seahorse.png, a seahorse;
• sierpinski.png, the Sierpinski triangle;
• sines.png, a kind of bar plot of sine functions, created by BAR_PLOT.
• snail.png, a snail;
• snap.png, a murky black and white snapshot of a mother and child.
• south_carolina_logo.png, a sports logo for the University of South Carolina.
• star_field.png, an astronomical image of many stars.
• stomachion.png, an image of the pieces of Archimedes's stomachion geometric dissection puzzle.
• surfs.png, a black and white beach picture whose contrast could be enhanced.
• tiler_3d.png, an image of the 3D pattern made by TILER_3D.
• tutte.png, an image of the Tutte graph, converted from a GRF file to an EPS file by GRF_TO_EPS, converted to a PNG file by ImageMagick Convert.
• underwater_bmx.png, a slightly blurred image of a bicycle rider on a diving board.
• usa_graph.png, a graph of the logical connections between states in the US.
• voronoi_sphere.png, a snapshot of a Voronoi tessellation of the surface of a sphere, with heptagons and pentagons marked. The starting point for the iteration used a set of spiral points.
• voronoi_sphere2.png, a snapshot of a Voronoi tessellation of the surface of a sphere, with heptagons and pentagons marked. The starting point for the iteration used a random set of data.
• vt_logo.png, a circular logo for Virginia Tech.
• vt_logo2.png, a circular logo for Virginia Tech.
• vt_logo_sports.png, a sports logo for Virginia Tech.
• vt2_logo.png, a rectangular logo for Virginia Tech.
• washington.png, a silhouette of George Washington.
• white_box.png, a white box.
• yonsei_logo.png, a logo for Yonsei University, Korea.

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