Posted: Fri Jul 15, 2005 11:53 am Post subject: Reducing images for the web
Alright, as you may or may not know, I'm a digital photographer. For my line of work, the bigger the file size, the better (in terms of quality for printing). I'm used to dealing with raw images that are 300 dpi and roughly 47mb (taken with a digital medium format camera). Needless to say, I can't quite figure out how to get an image so stinkin' tiny that I can post it on the web. Example, I've got a sig that I made about a month or 2 ago, and I've tried to post it on the "design review" forum, but the only way that I can shrink down the file size to below 200k is to either change the dpi (which is already 72) or to reduce the percentage in Image>Image size, which makes the entire image shrink (literally!). The sig is an animated .gif. Any clues or suggestions on how to make things a smaller file size without making the actual image smaller? _________________ All gave some, some gave all.....Lest we forget that war produces veterans, wounded both mentally and physically, and it is our job to help them now, as they have already helped us all in ways we will never know, and in ways that we take for granted every day.
What are the pixel dimensions of your sig? (72 ppi is kind-of meaningless)
Is it possible to reduce the number of colors in the gif color palette?
Or maybe reduce the number of frames in the animation?
Sorry, I'm used to dealing with a fixed image size of a standard photo crop and dpi. The image is 486 by 108 pixels. I have no clue what you were saying about reducing colors in the .gif pallete. As far as reducing the number of frames, it would take away from the effect that I was trying to get, and I've already cut a bunch of frames out, from 180ish down to 55. Now, what about reducing the amount of colors in the gif options??? _________________ All gave some, some gave all.....Lest we forget that war produces veterans, wounded both mentally and physically, and it is our job to help them now, as they have already helped us all in ways we will never know, and in ways that we take for granted every day.
View at 100% - if it looks bigger than you want it displayed on web (glossing over a lot of stuff here), then reduce the pixel dimension. Decrease pixel dimensions until it looks the size you want it to look on the web at 100%. (Or until it fits the parameters of the site where you will post it. Yes, it will reduce image quality. Maybe keep an original higher-res for repurposing later.)
Reduce number of colors. In IR open the file and have the preview window show “2-up” Invoke the Optimize palette, choose gif format and see how reducing the colors (below the 256 max) affect the image quality in the preview. It may look great at 32 colors. Choose what you can live with. Save Optimized.
With a GIF, you can reduce file size by lowering the color count to 128 or 64 or 32 or even 16 or 8, depending on how many colors are in the image. Say it is an image with only black and white and red, then you could get away with a small amount of colors. JPEG's are entirely different, but they do not support animations.
Unless you reduce the image itself, by reducing the pixel dimensions, as cbadland indicated, you are stuck. Or you can throw out some more frames.
Animated GIF's can be relatively large files. Play with the color count in the "Save for Web" feature.
And as cbadland said, forget about resolution, that is completely meaningless unless you print it. Pixel dimensions are the only thing that matters for the web.
So, would I be better off when I'm designing something for the web, to just use "web colors only" in the colors pallate? Would that help to keep the size down too? _________________ All gave some, some gave all.....Lest we forget that war produces veterans, wounded both mentally and physically, and it is our job to help them now, as they have already helped us all in ways we will never know, and in ways that we take for granted every day.
So, would I be better off when I'm designing something for the web, to just use "web colors only" in the colors pallate? Would that help to keep the size down too?
Yes, no, well... it depends. I'd try out the various color reductions algorithms on your file. Some pics, especially photographic images, I would not recommend restrictive ("web safe") colors- too much loss in image quality. Experiment and compare with various methods. That’s what the "4-up" preview is for.
I don't think "web safe" colors would have anything to do with the question of making a smaller file.
Web safe colors mean that they are recognized by both Windows and Mac platforms. That is irrelevant to your issue.
How about knocking out any more frames that you can, size it down to the least amount of pixels that you can, and save as a GIFF starting with 4 colors, then 8 and on and on until you think it is acceptable with the least amount of colors.
That’s about all you can do.
Why don't you post your animation here. Lets take a look at it.
I don't think "web safe" colors would have anything to do with the question of making a smaller file.
That's what I thought, but I ran a couple quick (and totally unscientific) tests comparing a 64-color Restrictive "web safe" palette to 64-color Adaptive, Selective and Perceptual files. For some reason the Restrictive "web safe" gif files were slightly smaller (but looked awful).
It looks crappy cuz I've tried to lower the resolution and color depth on it, but blaaaahhhhhh.....looks kinda blah. _________________ All gave some, some gave all.....Lest we forget that war produces veterans, wounded both mentally and physically, and it is our job to help them now, as they have already helped us all in ways we will never know, and in ways that we take for granted every day.
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