On my Delphi 5 site there's a simple image viewer. It's only a little thing, but it got lots of positive feedback. People found it provided just the capabilities they wanted, without being intrusive or bloated.
You liked my Delphi 5 Image Viewer - and this one's even better! The fast, multithreaded thumbnailing means that there are no extra 'thumbnail' files left on your computer. The explorer-style tree view is now the standard one provided by the Delphi 6 Shell Controls, and the Twain stuff now supports more Digital Cameras & Scanners.
And all source is included! Download Image Viewer Here!
If you want to recompile ImageViewer you'll also need to get the following packages:
My Low Level Utilities package
My Graphics Utilities package
My Miscellaneous Components package