But this is not the case. PNG supports transparency, but only if the image data was created as such. An image can also be saved as a PNG without being transparent.

Support for creating, editing, and saving transparent PNG images goes hand in hand with support for layers, since it's useful to be able to pull a single object out of an existing image so you can ...

Steps to maintain transparency when resizing PNG images. Let's get real. This is how to make sure your PNGs always look sharp and honest when you resize them: 1) Always start with a high-quality PNG.