Animated PNG images (APNG) have been around for quite a while in an attempt to add this functionality of the GIF format to PNG images. According to Wikipedia they are supported in Opera (>= 9.5) and in Firefox (>= 3.0). The first frame in the APNG animation is displayed if a browser doesn't support APNG images, since it was defined as an extension of the widely supported PNG format. Suppose you have an animated PNG that you want to show in your site and you want to warn your users if their browsers doesn't support it. How would you do it?
+2
A:
Make the first image display for a very short period of time, and have it be a big, ugly error message.
Adam Jaskiewicz
2009-05-14 23:12:04
An example of how this looks: http://people.mozilla.com/~dolske/apng/demo.html
Ben Blank
2009-05-14 23:22:45
+1
A:
If the first frame isn't a useful image, and the animation is crucial, it's probably too early be using them in your website. Better to wait until more browsers support it.
If for some reason they're vital and must be used then I'd include an error message in the first frame like Adam Jaskiewicz suggested, however, users that support APNG will see the warning for a brief period of time.
Apparently support can be detected as in this article on Ajaxian
David Caunt
2009-05-14 23:15:38