Re: ICO files are not simply renamed BMP files
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On occasion, you may come across files which have a .ICO extension that are not true icons. These are usually simple bitmap files which have simply been renamed by persons who are unaware of the differences in file format specifications. Some systems will actually display these files as icon-like images, but they also will cause problems under some Windows versions. If you come across such a file, and have problems accessing it, you should try renaming the extension from .ICO to .BMP and importing the image. Since such files do not contain true transparency or other icon attributes, you will have to edit and use File/Save As to create an icon in true ICO format.
from
http://www.cursorarts.com/help/icon/glossary.htm —
Regards
John Waller