VueScan supports over 1500 flatbed and film scanners and 321 digital camera raw file types, and is available for Mac OS X, Windows and Linux. It automatically adjusts images to optimum color balance, which reduces the need to manually do this in Photoshop.
Vextractor is a tool for converting raster images to vector by drawing centerlines and outlines. Vextractor can be used for vectorizing drafts, maps, schemes, logos, charts, etc.
XnView shell extension is an extension for windows explorer. Come to discover XnView, a software to view and convert graphic files, really simple to use! Support of more than 400 graphics formats! It's free, so do not hesitate!