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What Are PNG Images and Why Do I See Black Rectangles?

PNG stands for Portable Network Graphics; it is an alternative to the patent-encumbered GIF format.

The PNG image format has existed for many years, but was given a boost for mainstream usage when Unisys flexed its patent muscle:

"PNG was designed to be the successor to the once popular GIF format, which became decidedly less popular right around New Year's Day 1995 when Unisys and CompuServe suddenly announced that programs implementing GIF would require royalties, because of Unisys' patent on the LZW compression method used in GIF" (from http://www.libpng.org/pub/png/#history).

Many people are strongly in favor of the switch to PNG, as is evidenced by the Web site http://www.burnallgifs.org.

I Can't View Some PNG Images. Help!

We have noticed that Internet Explorer does not properly render some png images, showing the user black rectangles instead of the pictures.

We tried Internet Explorer 6, but that still did not solve the problem for us.

Try one of the following browsers if you have a problem with Internet Explorer:

Following is a test image:
(test-png.png)

Last Updated: 11/8/06