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BMP - Windows Bitmap (.bmp) format is an historic file format that is still widely used. It was developed by Microsoft® as a device-independent bitmap format, i.e. the image data is stored in such a way that the image can be displayed by Windows® on any type of display device. In general, it is not the preferred format to store images because it is not supported on other platforms such as Mac®.
JPG (or JPEG) – The Joint Photographic Experts Group (.jpg) format is optimized for photos and other “continuous tone” images. That is why it is the format of choice for most digital cameras. Its compression scheme analyzes an image and “discards” those pixels which the human eye most likely won’t notice. However, because it “discards” information, it is a lossy file format and if the compression is too strongly applied, you will see the effects of it! ("Lossy" simply means that some image data is "lost" in the compression process.) That said, huge savings in files sizes can be had (over TIF) without much noticeable degradation. It should be noted however that repeatedly saving the same file in JPG format will cause a cumulative loss of data which can very quickly become noticeable to the naked eye. If you need to edit a file, it is best to save the intermediate steps as TIF, then save the final version as JPG (if necessary).
PNG – The Portable Network Graphics (.png) format was developed to replace the GIF format in order to improve the severe lossy compression scheme as well as a counter to the proprietary licensing that GIF format requires. It uses a lossless compression scheme (i.e., no data is "lost" in the compression process) and while it doesn’t reduce file sizes as much as GIF, it completely preserves the original data. It also supports transparency and perhaps because of this is a popular format for sharing digital scrapbooking elements.
TIF (or TIFF) – The Tagged Image File Format (.tif) is a flexible format that can be both compressed and non-compressed. The compression (if applied) is lossless, but is not universally supported. (Kaleidoscope Kreator does not support compressed TIF files.) Because of this, files saved in TIF format are often not compressed and thus quite large. However, TIF is still the standard choice for archiving images that you want to keep for years to come because it is non-proprietary and contains all of the “original” data, including the color mode and image size information.
Windows® and Microsoft® are registered trademarks of Microsoft Corporation.
Mac® is a registered trademark of Apple Computer, Inc.
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