This document describes PNG (Portable Network Graphics), an extensible file format for the lossless, portable,
well-compressed storage of static and animated raster images. PNG provides a patent-free replacement for GIF and can also
replace many common uses of TIFF. Indexed-color, greyscale, and truecolor images are supported, plus an optional alpha
channel. Sample depths range from 1 to 16 bits.
If you know why you need alpha channels, of course you’re going to save in an appropriate format. But most casual users aren’t going to care. They took a picture of their breakfast or dog and just want to upload now. I’m not arguing PNGs serve no purpose; I’m arguing that most people aren’t Web or app designers. They don’t care whether it’s lossy or lossless, let alone about transparency.
If you know why you need alpha channels, of course you’re going to save in an appropriate format. But most casual users aren’t going to care. They took a picture of their breakfast or dog and just want to upload now. I’m not arguing PNGs serve no purpose; I’m arguing that most people aren’t Web or app designers. They don’t care whether it’s lossy or lossless, let alone about transparency.