For your first question, we allow the users to store the images as files on the disk or as binary data within the database. Some of our clients use only SQL Express, and with the 4GB DB limit, we still need to allow them to store the files on disk. However, with the full version of SQL, they can store them in binary fields in the DB.For your second question... If you're just showing JPEGs or BMPs, then you don't need Atalasoft... TIFFs even for that matter. You will need Atalasoft if you need to add scanning support to your application, to allow your users to scan directly from your application. Once you have the data as an image file, you don't have to have Atalasoft to display the images... a .NET PictureBox set to the right dimensions will work just fine.
We also use Atalasoft for PDF rendering, so, when users scan documnets into the app, they are stored as PDFs and rendered through an Atalasoft control.