Can't add image to image list on wxMSW

[Hyrum K. Wright]

I've created an ImageList to use with a ListCtrl, but I'm experiencing
some odd behavior.  When I try to add one of the images to the ImageList
on MS Windows, I get a dialog saying "Couldn't add an image to the image
list", and the image does not appear in the application.  Other images
work fine on Windows, and the image in question gets added to the image
list correctly on Linux.  I've tried different image formats (of the
same image), but the problem continues.

Is this a bug, or could I be doing something wrong?  I can post relevant
code upon request.

This is with wxPython 2.6.3.3 on WindowsXP.

-Hyrum