[> By default, a tif image cannot be viewed in IE. Therefore, you had
[> better convert the tif image to other format like jpg first.

TIFF is lossless in most cases. So PNG seems to be a better thing as it's
lossless as well, while auto-converting to JPEG may affect the image quality.

[> I am
[> afraid there is no a way to show tif in ASP.NET directly.

Seems to me that .NET has built-in support for TIFF (as there's such thing
as ImageFormat.Tiff), so you can convert it even on-the-fly using ASPX by
loading the TIFF into a Bitmap object and then converting it into a stream
of PNG format, and setting all the response headers to a format appropriate,
of course. But that's a significant load on the server, so I wouldn't do
it on a regular basis.

(H) Serge