Transparency instead of white in PNG

[pscheven]

Hello.

On my first computer, when I delete a zone in a PNG file with the Delete key and I save it, the deleted part is transparent.

On my second computer, when I delete the same zone in the same PNG file and I save it, the deleted part is white.

The two computers both run Paint.NET v3.36.

Previously, my first computer behaved as my second computer but something has changed and I don't know what. I have tried to uninstall Paint.NET and to reinstall it to go back to default configuration but it doesn't change anything.

Can you please help me ?

Thank you.

Patrick.

[Simon Brown]

Are you viewing the saved file in Paint.NET in both cases?

[Myrddin]

Are you saving as a 32-bit PNG rather than 24-bit?

For context: 32-bit can handle transparency, 24-bit cannot.

[Rick Brewster]

Just use Auto. It'll only use 24-bit if all pixels are opaque. If there's any hint of alpha, it uses 32-bit. I'm honestly not sure why you'd ever want to specifically choose 24- or 32-bit

[ragingsuns]

That, or you may have forgotten about the white background layer that comes default with all new documents. XD

[pscheven]

Hello.

Thank you for your answers.

When I choose Auto, it seems to automatically save at 32 bit format.

How can I disable that alpha setting or enable the white background again ?

Thank you.

Patrick.

[Myrddin]

If you want to have a white background, then you can either:

1) save as 24-bit, which will default any transparent pixels as white; or

2) as ragingsuns pointed out, have a white layer underneath your image, flatten, and save with 'Auto' selected. This will have it saved in 24-bit.

Just use Auto [...] I'm honestly not sure why you'd ever want to specifically choose 24- or 32-bit

Personally, I like to have my awkward knickers on and purposely bypass clever features you build in.