I'll add more here as I figure this out. How to get my asp.net app to see network resources.

I know the problem is that the web pages are being run as ASPNET account - non privileged machine.

Can tweak processModel attribute in machine.config, but it's machine wide change. (According to docs, can't override this in the web.config)

Here's an article about using a serviced component. I'm assuming this works, since it runs in COM+, which can be set to any identity.

15 Seconds : Accessing Shared Resources Using ASP.NET

From Visual Studio Magazine. Two things need to be in sync when using SQL Server Session State across multiple machines in a web farm.

#1 - all machines must have a consistent "machine key" machine.config.

#2 - the application path for all web sites on all machines must be the same in the IIS metabase.
(i.e. \LM\W3SVC\2 )
If one machine has more web sites than the others, it's likely to have different application paths. You have to tweak the IIS metabase to fix this.

See KB article 325056 for info.

Upload files with File Field Control

Should try to incorporate this with the nGallery image site.

ASP.NET Home: Uploading Files Using the File Field Control (ASP.NET Technical Articles)

MSDN "Application Blocks" for various design patterns and practices.

Includes Data Access Layer, Smart Client Offline, Caching in ASP.NET, Exception Management, .NET/COM integration, Application Updates, etc.

Microsoft patterns and practices for Application Architecture and Design