The same Doc Searls item points at zgp.org, leading to zgp.org/~dmarti, leading to burnallgifs.org, leading to The GIF Controversy: A Software Developer's Perspective from October 1999. This is an authoritative account of the problems with the GIF image format, including the points I looked for: JPEG is not an adequate substitute, but PNG is.
Rather, the document says PNG isn't yet, but I hazard to say it is a quite adequate substitute for vanilla GIF at this point. It's lossless, palette transparency is well-supported, and files are marginally smaller with maximal compression at the same color bitrate. PNG isn't yet everything it could be, since full flawless support isn't wide yet (which you know if you tried Stapler in a non-Gecko browser): alpha-channel transparency doesn't work in MSIE 5, Netscape 4, or Opera 5; and animation, part of GIF89a, is in a different format, MNG.
Yammer, yammer. If you were waiting for a handy tip about PNG, surprise: Gecko exhibits display artifacts with alpha transparency if the image is an odd number of pixels wide.
