\ #22226 libspng, pngsuite and png image for perf test

Author: ocpalo

testdata/highgui/pngsuite/PngSuite.LICENSE

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+PngSuite
+--------
+
+Permission to use, copy, modify and distribute these images for any
+purpose and without fee is hereby granted.
+
+
+(c) Willem van Schaik, 1996, 2011
+

testdata/highgui/pngsuite/PngSuite.README

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+        PNGSUITE
+----------------
+
+        testset for PNG-(de)coders
+        created by Willem van Schaik
+------------------------------------
+
+This is a collection of graphics images created to test the png applications
+like viewers, converters and editors. All (as far as that is possible)
+formats supported by the PNG standard are represented.
+
+The suite consists of the following files:
+
+-	PngSuite.README		- this file
+-	PngSuite.LICENSE	- the PngSuite is freeware
+-	PngSuite.png		- image with PngSuite logo
+-	PngSuite.tgz		- archive of all PNG testfiles
+-	PngSuite.zip		- same in .zip format for PCs
+
+
+--------
+    (c) Willem van Schaik
+	[email protected]
+        Calgary, April 2011
+