Someone told me that there was "image optimization" software that would remove certain unnecessary data from digital images to be used in web sites, to allow faster loading. Is there such a thing, beyond just shooting at a relatively low resolution and using small image dimensions? Thanks, Bill Spurlock

-- Bill Spurlock (WAspurlock@aol.com), January 15, 2000

Answers

I don't think any software could be smart enough to know what is 'unnecessary data'. But there is plenty of software around that will compress images. The more aggressive the compression, the smaller the file, but the worse the visual appearance.

'JPEG Quality Explorer' (available here will let you interactively explore compressions.

-- Alan Gibson (Alan.Gibson@technologist.com), January 15, 2000.

That URL needs a password. This one doesn't.

-- Alan Gibson (Alan.Gibson@technologist.com), January 15, 2000.

here is a tip that I got from Tipworld.com for Photoshop (5.5) "As you've probably seen on the Web, most images render top-to-bottom. In today's immediate-gratification Web world, the second or two wait for the full image is an eternity. Luckily, both the GIF and PNG formats have an option that immediately displays a low-resolution image and gradually builds the full image as the graphic download completes. This creates the illusion of a faster download.

"To create an interlaced GIF or PNG file, choose File, Save For Web. In the resulting dialog box, select GIF or PNG-8 or PNG-24 from the File Type list box in the Settings section. Then, select the Interlaced check box and click OK. Finally, name your file and click Save. "

I don't know if other programs with save as interlaced will have the same affect.

-- David Erskine (davide@netquest.com), January 15, 2000.

Some tips: ----- Photoshop designers were too enamoured with images to AGRESSIVELY compress jpegs.

Even the worst quality setting in Photoshop saves fairly good (but unnecessarily fat) jpegs. For unimportant images, such as small jpegs that act only as thumbnails to larger version of same, you can use programs other than Photoshop to REALLY compress those pixels.

I use Micrografx Picture Publisher version 8 (available at Buycomp for about $40 at http://www.buy.com/soft/category.asp?sec=4 ) It allows variable compression & you can see the result on-screen before you save.

----- For GIFs it IS possible for programs to analyse image & remove unnecessary info. For example, many people save GIFs with larger color palette than actually needed. A program can count the colors actually used and reduce the palette if appropriate.

There is a service available on the net: you send it a GIF file and it sends you back a better compressed one, if possible. It is put up by a company that sells program to do this. Sorry, I forgot the URL. Maybe others know it.

-bruce

-- bruce komusin (bkomusin@bigfoot.com), January 16, 2000.

As with the program mentioned above, PhotoImpact 5 (Ulead)lets you see various compression schemes before you decide. Also does color optimization for the Web that you can view before you decide to accept it or not. Also has a feature where you can select a modem speed and get an idea of how long it will take your image to load.

-- Eileen Morrisot (we108918@nassaulibrary.org), January 16, 2000.

read the topics in photo.net re: preparing images for publication on the web. Avoid progressive loading; takes longer to load image, use images below 500pixels in size, save at a jpeg compression level of 5 or 6. don't include a preview in your save preferences. You should have an image in the 25-40K range. That should load fairly quickly

-- jonathan ratzlaff (jonathanr@clrtech.bc.ca), January 17, 2000.