PABretherton
Premultiplied alpha (PMA) is a special kind of alpha blending setup. It requires colors to be stored in a special way, different from how regular images on the internet are usually saved. Saving for PMA makes images look weird when you open them in a browser or image editing program, because they're only meant for rendering in a specific way.
Many modern programs and frameworks (assuming they did their homework) will handle the details of PMA for you so you don't have to do anything special. It lets you save and use images normally while it internally does PMA to account for quirks in rendering.
Without PMA means you'll be saving and editing regular images as you commonly would. And you can import and edit and export PNGs normally.
I think you were also imagining that the transparency becomes like a GIF where the pixels can only be fully opaque or fully transparent. This is not the case. These are regular PNGs. They will be rendered like PNGs as you expect unless you explicitly program it (in Flutter) to render in a different way.
