On 05/21/2008 03:02 PM, Hendrik Boom wrote:
I've noticed that some 40K byte jpeg files are very good, as good as ones ten times the size, and that others are awful. The question naturally arises about the proper way to further compress the large images to save disk space.What image compression programs have people found to give good results?And to what extent is good image quality the result of the algorithms that display the image, adjusting image size to screen size and resolution and the like?-- hendrik
First, you can't recompress JPEGs without degrading them permanently, so don't do that unless you don't care about the data.
Second, I've heard that progressive JPEG compression can outperform "normal" JPEG compression, so you're probably witnessing the advantage of progressive JPEGs. The program cjpeg (part of libjpeg-progs in Debian) can create progressive JPEGs.
HTH