ViewPic

ViewPic is a lightning-fast image viewer which allows you to quickly browse through all the images in a folder. It's designed to improve your image-viewing experience on OS X.

• Better image viewing experience ViewPic features a neat, standard interface, with all function buttons on top, and thumbnails below. Each of them will hide automatically and display when you need them. You can even view image in chromeless mode, so you can avoid unnecessary distraction when viewing images.
• View thousands of images in a folder Still using Preview to view images one by one? Now you can drag multiple images to ViewPic, or simply open a folder directly, and press back and forward to view all images quickly and smoothly.
• Super-fast viewing Display your photos--including large image files--rapidly and with no loss of quality. You can view your images in real-time since you never have to import them into library first.
• Convenient viewing options You can also adjust the image for better viewing with options to flip horizontal / vertical, rotate, resize, etc., plus convenient functions such as zoom in/out, fit to screen, 1:1 original size, etc. All function buttons are available in the toolbar.
• Other useful features
• If you want to set a photo as desktop wallpaper, simply click on "Set Wallpaper" in the toolbar.
• Browse all imported image thumbnails for quick navigation.
• Resize an image.
• Set ViewPic as the default image viewer.
• Customize the viewing background color as you wish.
• Supports all mainstream image formats, including PNG, BMP, GIF, JPG, JPEG, ICNS, TIFF, TIF, PSD, etc.