You do not need to save images into Image File Sets unless you need Ranger compatibility with large Unisys check scanner/sorters. You can access the images in the Ranger "InPocket" event via the GetImageAddress() and GetImageByteCount() functions.
If you do need to use Image File Sets, the sample program "Automated Image Extraction" demonstrates how to read the Image File Sets using our SeqUtil.ocx ActiveX control.