Valid values: | none, defined, premultiplied |
Default value: | none |
If set to none, the default, any wizard image which is a 32-bit .bmp file should not have an alpha channel.
If set to premultiplied, any wizard image which is a 32-bit .bmp file should have its red, green and blue channel values premultiplied with the alpha channel value.
If set to defined, any wizard image which is a 32-bit .bmp file should not have its red, green and blue channel values premultiplied with the alpha channel value.
This directive has no effect for a wizard image which is not a 32-bit .bmp file.
To create transparent .bmp files compatible with Inno Setup, you can use Paint.NET, a free image editor. Open your transparent image in Paint.NET, save it as a 32-bit .bmp file, and then set this directive to defined. These files may appear large, but Inno Setup compresses them using LZMA, which typically achieves better compression ratios than, for example, PNG compression.
See also:
WizardImageFile
WizardSmallImageFile