The first row tests that alpha PNG images are correctly displayed as part of an SVG image, ignoring the background colour in the image which is only used to display the PNG image stand-alone.
The second row tests indexed PNG transparency (tRNs), again checking that the background color is ignored when displayed as part of an SVG image.
This test uses the PNG Group test suite created by Willem van Schaik.
Run the test. No interaction required.
The test is passed if all the small PNG icons are displayed as in the reference image.