Saving to an opacity channel

[scardario]

Hi everyone

Is there a way in Designer or Photo to save a grayscale image to an opacity channel without the others channels being affected? I'm a game developer and want to store as much information as possible in a single image file. When I mask the image or multiply it the other channels are lost in the resulting image(it's logical since they won't be seen in a conventional software/viewer)

Thank you.

[toltec]

47 minutes ago, scardario said:

Is there a way in Designer or Photo to save a grayscale image to an opacity channel without the others channels being affected? 

You can indeed create spare channels in Photo, but not Designer.

Try right clicking on things in the Channels panel for various options.

You can also save pixel selections as spare channels. Select > Save Selection > As Spare Channel.