AGAST - Creating Sprites with an Alpha Channel

Tutorials: Creating Sprites with an Alpha Channel

This tutorial explains how to add an alpha channel using a few major paint programs.

When creating the image, choose RGB color.
Go to the Channel palette. Alt-Click on New Channel (the options for color and opacity are not relevant to AGAST).
To paint on the alpha channel, select it from the Channel Palette. You can only paint in greyscale. To AGAST, white (255) means fully opaque, and black (0) means fully transparent.

When creating the image, choose 16.7 million colors (24 bit).
You can create an alpha channel in a couple of different ways. The one I favor is complex, but gets good results. I copy my picture to the clipboard, then paste it as a new image. I convert the new image to grayscale, then paint over it with the greys.
Then I go to Masks|New|From Image... and turn it into a mask. Then I do Mask|Save to Alpha Channel, select my original image from Available Documents, and hit Okay.
Then I save that image in .PSD format.

When creating the image, choose 24-bit RGB. Go to the Channels tab. Click the little arrow in the upper right, then New Channel (the options for color and opacity are not relevant to AGAST).
To paint on the alpha channel, select it from the Channel tab. You can only paint in greyscale. To AGAST, white (255) means fully opaque, and black (0) means fully transparent.