FastStone Image Viewer is an image converter, editor and viewer program developed by FastStone Soft. The program is used for viewing, managing and comparing images. Some of its features also include red-eye removal, cropping, emailing, color adjustments and retouching. Images can be viewed in full-screen mode providing access to EXIF information, major functions and thumbnail browser. Its full screen mode also has an image zoom support and fly-out menu panels. Image browser user interface is similar to Windows Explorer making it familiar to first time users. Its image viewing functions uses LAnczos resampling algorithm. It offers dual head configuration support and custom order arranging through DnD. The program also comes in a portable version where no installation is required.
Fast Stone Image Viewer supports all main graphic formats including WMF, BMP, JPEG, GIF and PNG. The program offers 11 resampling algorithms when resizing image files. It also offers image color effects like sepia, gray scale and negative. For adding effects, the program has tools for annotation, drop shadow, sketch, oil painting and more. Its image management features include tagging capability, copy to/move to folder support and drag-and-drop. For image comparison, users can compare files side-by-side to up to four files simultaneously. It also has a batch processing feature allowing users to convert, rename images.