posted May 12, 2003 09:18 AM            

I use a Sony Mavica CD250 digital camera, which stores pictures on mini CD's in .jpg
format. Once the CD is finalized, all I need to do with the images is to email them. My
problem is the pictures need to be large in size and have high resolution, so many of
them are around 950k in size .

My goal is to reduce the size of the images to speed up the emailing process . Winzip
doesn't take much of a bite out of the file size, and every application I've found
on the internet for compressing .jpg files is extreme overkill or inefficient.

At this point, it doesn't matter how I make the images smaller (compressing, converting to
another format, etc). The person(s) who receive the pictures are simply going to open them
for their own analysis, and it really doesn't matter to them what file size or format they are,
only that they retain their size (roughly 1600 x 1200 pixels) and resolution.

Thanks in advance for the help!

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Mark Pruitt
markspruitt@yahoo.com

posted May 12, 2003 10:25 AM            

This is just a thought, why not setup your own custom web server for your clients to download from. The web server really wouldn't need all the bells and horns that the others have. I did something like this last year some time so a friend could download some maps for a game we played. You could make a really quick and dirty version that strips all the useless junk from the browser request and just focus on the GET [filename] portion. You would then only email the links to your server and the files to the client, you could even add some special strings in the link for added security. If you want I could maybe find my little project and send it to you Other than that I'm not sure what else you could do to make these images smaller. Image compression and data compression in general seems to be a thorn in the side for us programers

posted May 12, 2003 11:27 AM            

JPG files are already compressed. Otherwise they'd be uncompressed
bitmap files.

Winzip and the like will get you very little (if any) additional
compression on an already compressed file.

What you could do is change the compression quality on the images.
This will allow them to shrink in disk size while maintaining the
dimensions. Only drawback is loss of quality.

posted May 12, 2003 11:27 AM            

I wasn't thinking about a multipart solution. However, if I can find a way to
reduce the size of the files some (not unusual to have 40mb to 60 mb of photos,
and even over DSL it gets pretty painful), and let the users download them, that
will still work!

posted May 12, 2003 11:49 AM            

> it really doesn't matter to them what file size
> or format they are, only that they retain their
> size (roughly 1600 x 1200 pixels) and resolution.

That's called "lossless compression", i.e. no information is lost. Any ZIP compressor will do that for you. The problem is that, as George pointed out, JPEG files are already compressed. So ZIP (et al) won't do much for you -- if anything -- in most cases.

JPEG is really a compression format not an image format. It's simply a compression format that has been optimized for certain types of images.

So about your only options are to 1) use zipped bitmaps and see if they are smaller than the JPEGs, or 2) tell your JPEG-creation program to create smaller files, but because JPEG is a "lossy compression" technique, that always involves an additional loss of quality (resolution). Even a top-quality (100-quality) JPEG file will be of lower quality than the original bitmap. Always.

Depending on the image contents it's very possible that GIF files will produce acceptable quality and smaller files. But then you get into licensing issues, because GIF is owned by a company which requires you to pay royalties if you sell a program which uses GIF compression.

HTH.

-- Eric

------------------
Perfect Sync Development Tools
Perfect Sync Web Site
Contact Us: support@perfectsync.com

posted May 12, 2003 02:12 PM            

Loss-less image compression tools.
http://www.bitjazz.com/