I have written about FastStone Image Viewer here on the blog in the past and can attest that it is probably one of the best, if not the best, image viewer out there. As a matter of fact, it carries a 5 star CNet rating. I think if you use it you will find that it is more than just an image viewer
FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor. It has a nice array of features that include image viewing, management, comparison, red-eye removal, emailing, resizing, cropping, retouching and color adjustments. Its innovative but intuitive full-screen mode provides quick access to EXIF information, thumbnail browser and major functionalities via hidden toolbars that pop up when your mouse touches the four edges of the screen. Other features include a high quality magnifier and a musical slideshow with 150+ transitional effects, as well as lossless JPEG transitions, drop shadow effects, image annotation, scanner support, histogram and much more. It supports all major graphic formats (BMP, JPEG, JPEG 2000, animated GIF, PNG, PCX, PSD, EPS, TIFF, WMF, ICO and TGA) and popular digital camera RAW formats (CRW, CR2, NEF, PEF, RAF, MRW, ORF, SRF, ARW, SR2, RW2 and DNG).
For example, buried in Fastone Image Viewer is an option where you can scan documents and save them as PDF files. I personally use this all of the time to convert my paper documents to the digital PDF format.
To get to this feature, launch FastStone Image Viewer, click on the File menu, and select Acquire Image From Scanner.
You will then be taken to the Acquire Image From Scanner workspace where you simply click on the scan button to begin your scans.
Typically, by default, this will launch your scanner software. You can scan single documents or perform batch scans were you scan one document after another. When done, select save and select the PDF Format option.
Also, on an added note, you can also save image files in FastStone Image Viewer to the PDF format, as well. Very powerful image viewer utility that can either be installed or used as a portable app.