Image Quality

I am creating this thread here after being in a similar discussion on another forum that has an area for webmasters (not for professionals). A thread went off into a tangent of "saving bandwith" with images, and someone insisted the way to save download time on photos was to convert them over to gif's since borwsers can't display all the quality of the pictures a camera takes.

Well I went and created this page: http://66.39.121.82/imgtest/quality.html to give an example of how for photos it is best to use a JPEG instead of GIF. I took the same image and using Fireworks, created each image with the settings listed. For JPEGs, I used no smoothing. For GIFs, I didn't use dithering. For the JPGs, with the lowerfile size you can start to notice the effect of the compression on the sharp ede lines of the walls to the right of the fireplace. for the GIFs, you can really notice the lack of colors in the areas with shading, like the white shaded area above the fireplace. As you can see, you have to take a gif to the lowest setting (only 16 colors) to get a file smaller than the JPEG at 80% which is the setting I usually use for photos.

For those new, some programs use different number values for the compression setting of the JPG's. Fireworks uses 0-100% quality setting, where 100% is the least amount of comrpession (larger filesize). Other programs may give you an option to set the level of compression, where smaller the number gives you the sharper picture (larger filesize). Also I have seen some programs that use a scale of 0-255. Play around, see what works best for you. The image optimier link above looked pretty good to demonstrate differeces.

Someone posted a link to the following page which at quick glance looks like it could be useful to those who want something quick http://tools.dynamicdrive.com/imageoptimizer/

Myself, for optimizing images, I have been using Ulead's Smart Saver Pro (http://www.ulead.com/ssp/runme.htm ) While many programs allow you to do this inside them, I just got used to this program for opitmizing images, creating image slices, and making complex iamge maps. The big thing I liked about this program was the ability to take an image and have just portions be sharper than the overall compression. I had a psicture one time that we needed compressed, but there was a sign in the photo. I was able to use high compression on the overall picture but yet hav ethe text on the sign still be sharp to read. Again, other programs may have this ability, this is just one I got used to several years ago (and it was well packed with it's features then, that they still sell teh same version today.)

-Greg