How do I convert a JPG into a 50% transparent PNG?

[xberg]

Hi,

I want to transform any JPG into a 50% transparent PNG.
I found how to make a specific color fully transparent with:

Code: Select all

magick convert 1.jpg -fuzz 8%% -transparent white 1.png

But I don't want this: I want all the JPG to be a 50% opaque PNG.

Thanks

[snibgo]

Code: Select all

magick in.jpg -alpha set -channel A -evaluate set 50% +channel out.png

[xberg]

Thank you!
Great!! What's the +channel at the end for?

[snibgo]

"-channel A" means "apply all following operations to just the Alpha channel". "+channel" means "set the default, which is that all following operations apply to all channels".

In this case it is superfluous, but good practice is: whenever you have a "-channel", you should always have a "+channel" somewhere.

[xberg]

Thanks! Great explanations