At 01:14 PM 12/9/99 -0000, Les Cowley wrote: > >I recently had occasion to post several megabytes of images for >an article and found that if an image (or several) is compressed in >a zip file then there can be substantial savings in size. The amount >of (zip) compression depends on the image. Zip compression >does not cause any image degradation. > >Les Cowley > I agree that compression is the way to go with graphic files, but what you use and how much you benefit depends on the type of file that you are compressing. JPEG files are already compressed. You do not gain a lot with further compression. Let me give an example from recent personal experience.
One of the Christmas gifts I am sending out this year is a personalized screen saver using pictures scanned in from the family album. My system is fairly elementary. I could only save the scanned pictures as bit maps (bmp or tif) files. At the resolution I wanted, each picture was over 1.3 MB. ZIP gave me a 40% compression which was useful but not a solution. Using the Print Screen tip to save files to the clipboard allowed me to import the files to Powerpoint and save the files as GIF or ppt files for 90 and 75% savings. There was a noticeable quality loss, particularly for the gif files as the gradations in colour were lost. The ultimate solution was to download LView from the web <http://www.lview.com> and use it to save the bmp and tif files as JPEG files. The compression was over 30 times! Although JPEG is a lossey compression, the quality was indistinguishable for me from the originals. Each picture is now a manageable 40 kb file. The batch of 10 pictures is about 400 kb, one third of a single uncompressed file. This I can afford to distribute to my relatives and they can afford to download the images. If Tony's pictures are JPEG, they are already well compressed. Can I get added to your list Tony? Cheers, Roger Bailey N 51 W 115
