still, make sure that the ‘Preview’ toggle is on and then watch the image area and change the compression level by moving the ‘Quality’ slider down. You can see the quality of the image changing, especially Figure 3.19: Example for High JPEG Compression (a) Quality: 0.06; Size: 1361 Bytes (b) Quality: 0.42; Size: 3549 Bytes Figure 3.20: Example for Moderate JPEG Compression (a) Quality: 0.85 (GIMPs default); minimizing the loss of image quality. No other format comes close to achieving the same level of compression. It does not, however, support transparency or multiple layers. For this reason, saving images

image compression is achieved by using the JPG format, but even if the image is already in this format, you can usually still make it take up less space, as the JPG format has an adaptive compression scheme scheme that allows saving in varying levels of compression. The trade-off is that the less space an image takes, the more detail from the original image you lose. You should also be aware that repeated saving degrees of compression: Figure 3.25 Example for High JPEG Compression (a) Quality: 10; Size: 3.4 KiloBytes (b) Quality: 40; Size: 9.3 KiloBytes Figure 3.26 Example for Moderate JPEG Compression (a) Quality:

and opening images. Guash uses xv to create its thumbnail images. • gzip, to enable extra file compression/decompression of any image format. To check whether you have gzip, type gzip -h. If you get an message, either you have not installed gzip or it is not in your path. • bzip, to enable extra file compression/decompression of any image format. To check whether you have bzip, type bzip -h. If you receive directly into Gimp. • libtiff, to enable reading and writing of TIFF images. • libz, to enable PNG compression. • libpng, to enable reading and writing of PNG images. • libjpeg, to enable reading and writing

web site. You can save your image in PNG format with the default settings, but using maximum compression. Doing this will have no negative affects on the quality of the picture, as it would have with better off saving it as jpeg. The main thing is to find the best tradeoff between quality and compression. You can find more information about this topic in . Reducing the File Size Even More If you strictly need to be in the same directory when you drag the file, since it uses some kind of search algorithm to find it if it's not, but in any case putting it in the same directory does no harm. In principle

programs. JPG (or JPEG) Joint Photographic Expert Group Saves storage space using lossy compression. Most commonly used with digital photos. GIF Graphics Interchange Format Can only store for its ability to store animations. PNG Portable Network Graphics Provides better lossless compression than BMP and GIF. TIF (or TIFF) Tagged Image File Format Store one or multiple images in Image as JPEG dialog box. Set the compression quality. The Quality slider defaults to 90, but you can adjust it up or down to reduce or increase compression. GIMP NOTES UNIT IV D e v