CDR was a file format developed by the Corel Corporation and is used primarily for Vector graphic drawings. It is used as the default format from the Corel Draw application which was first developed in 1987 by Michael Bouillon and Pat Beirne who were tasked with developing a vector based illustration program that Corel could package with their desktop publishing solutions. In 2007 Microsoft took exception to the CDR format wrongly blaming it for some security vulnerabilities in it's Microsoft Office suite of products. They concluded that actually this was innacurate and developed a bunch of tools to allow users to import CDR files into MS Office 2003.
There is no publicly available CDR file format specification. It has however evolved over time from it's initial offering in January 1989 to the present day where it is a different beast to what was initially developed to include including support for color management and spot colors, and has a basic support for text.
JPG's are often used for web sites and email as they are generally smaller file sizes as they are lossy meaning that some image quality is lost when the JPG is compressed and saved. The resultant 'lossy' file means that quality can never be recovered. The JPG format is often used in digital camera memory cards. The JPG file is a great format as it often manages to compress files to 1/10 of the size of the original file which is especially good for saving on bandwidth.
JPG is a graphical file format for editing still images, it offers a symmetrical compression technique which is processor intensive and time consiming in both compression and decompression. JPEG is a joint standard of the International Telecommunications Union (ITU-T T.81) and the International Organization for Standardization (ISO 10918-1). JPEG involves a lossy compression mechanism using discrete cosine transform (DCT). Compression rates of 100:1 can be achieved, although the loss is noticeable at that level. Compression rates of 10:1 or 20:1 yield little degradation in image quality.
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