photo sizes

Aaron Wilson · December 11, 2004

what is a good way to take a 11mb pic and lower it to a 8mb pic with out loosing the quality and with out cropping it?

Shay Stephens · December 11, 2004

Aaron Wilson wrote:

what is a good way to take a 11mb pic and lower it to a 8mb pic with out loosing the quality and with out cropping it?

You can save it as a PNG which is a lossless compression scheme. A PSD format might get you there too.

Now if you are talking about taking an 11MP (megapixel) image and resizing it down to an 8MP image, then just resampling (resizing) it down and hitting it with a good unsharp mask will do the trick.

ubergeek · December 11, 2004

Downsizing
In order to reduce the image size, you're going to be throwing away some information, which if you're not cropping means reduction in quality. However, resampling from 11 megabytes to 8 will not appreciably reduce the image quality.

However, your question is a little strange. Why downsize at all? What makes 8MB the "magic" number? What is it that you're trying to accomplish?

Cheers,
Jeremy

Aaron Wilson · December 11, 2004

why to make them smaller
I see I had a typo... mp = mb... the reason is because smug mug has a cap of 8mb per pic as the pics are 11mb or 9.5mb and even 1 at 8.2mb... so ot post them i need them at a 8mb or less in size

dunno

dkapp · December 11, 2004

When you did save as *.jpg, did you use a setting of 12? If so, just reduce that to 11 or 10 and you will be golden.

Dave

ubergeek · December 11, 2004

JPEG compression vs. image resolution
Ahh, it all makes sense now. Yes, you can turn up the JPEG compression (i.e. turn down the quality factor) a bit to get a ~30% file size reduction, or you can resample the image to a lower resolution, or some of both. If you're at the very top of the range of JPEG compression (e.g. 99 out of 100), you can probably back it off to ~95 with no noticeable loss of quality. Beyond that, I would consider resampling the image to a smaller resolution, which will reduce fine details but won't introduce ugly artifacts.

A 10-megapixel (for example) camera doesn't really produce 10 "real" megapixels of information anyway, because 2/3 of the information at each pixel is actually interpolated. (That is, unless we're talking about a Foveon X3 sensor, but that's a different story.) So images from these digital cameras can be resampled to a somewhat smaller resolution without losing much information.

So in summary, I don't think there's a hard and fast rule for reducing image file size while minimizing quality loss, but a good general guideline is to bump up the JPEG compression only modestly, and then resample to a smaller resolution if you still need a smaller file.

Cheers,
Jeremy

iamagoo · March 28, 2005

Newbie Here
I've just signed up on a trial basis and this is exactly the problem I'm facing. I use a Canon 20D and shoot large JPEGS but when I load them on my computer I always convert them to TIFFs which are 23MB. After editing and then reconverting them to JPEGs they are usually well under 8MB, but I've just started sharpening in LAB mode and then converting them to JPEGs which seems to keep the file size quite large. Any suggestions?

Andy · March 28, 2005

iamagoo wrote:

I've just signed up on a trial basis and this is exactly the problem I'm facing. I use a Canon 20D and shoot large JPEGS but when I load them on my computer I always convert them to TIFFs which are 23MB. After editing and then reconverting them to JPEGs they are usually well under 8MB, but I've just started sharpening in LAB mode and then converting them to JPEGs which seems to keep the file size quite large. Any suggestions?

stay tuned..... you should be hearing something soon in this regard that could address this very issue

iamagoo · May 7, 2005

Anything been done in this regard yet?

photo sizes

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