What size should the background image in an MSI be?

Question

I am trying to create a Windows Installer package using Wix. I'm getting a lot of conflicting information about what size my custom background should be--the Wix documentation suggests a size of 500 x 314 pixels, but this leads to slight image distortion in the installer.

I believe that I may be indirectly using the SplashBitmap property in Windows Installer, whose documentation suggests 480 x 320 is the correct size. When I try to use this image size, I also get artefacts in the image.

Could anyone tell me what the correct size should be?

Answer 1

After a bit more searching, I found this on wixwiki.com¹, whose sizes worked correctly for me (using WiX 3). They are:

• Banner: 493 x 58
• Background: 493 x 312

Hope this helps someone else, too.

^{1: Note: this site does not longer host WiX content.}

Answer 2

The WiX installer dialog is resized anyway depending on the system DPI setting.

On a default 100% DPI setting, the correct size is 493 x 312 as answered above. But this is unfortunately multiplied by the DPI ratio, and scaled with a crappy nearest neighbor filter.

High DPI screens become more and more popular, and need a DPI setting higher than 100% in order to stay readable. WiX installer dialogs will look crappy anyway, unfortunately.