help needed - high resolution pictures and filesize problem

[turf]

i have some high resolution pictures that i want to make available for download to members of our sites but when i try and zip them the size of the zipfile doesnt really change much compared to how much space they take up unpacked..

So my question is is there a way to get a high resolution picture to shrink in filesize without loosing quality ? i have tried to strip them of exif info but that doesnt really make any difference as each file only shrink by aprox 200kb a piece..

To do a size comparison i checked out the size of 73 high resolution from femjoy and they state an aprox 75MB download for the images where as my zipfile would take up 260MB+ - so either i am doing something wrong or my pictures have too much junk in the trunk that my stripperprogram doesnt remove ?

any info on what to look for or how to shrink a hi resolution picture in filesize without loosing quality ?

[Toby]

Originally Posted by turf

So my question is is there a way to get a high resolution picture to shrink in filesize without loosing quality?

No, not really. Any type of image compression algorithm is going to trade file size for image quality and, as you already discovered, file compression software such as ZIP, RAR, etc. doesn't really gain you much.

[Cleo]

Jpegs are already compressed so zipping them isn't going to make them any smaller.

[SirMoby]

Winzip just came out with a new version that claims to zip JPEGs. I just an email about it a few days ago. I don't know if it's effective or not.

[Cleo]

One thing that helps a little bit is if you are using Photoshop to generate your images then be sure that you tell it not to include a custom icon or preview on the images.

[Toni]

You always loose some quality but you can save a lot in file size if you use a compression program, for example I use Ulead SmartSaver Pro

[digifan]

There is Boxtop ProJPEG, awesome.. see www.boxtopsoft.com .

[Max -RiotDesign]

Hi!, have you tried winrar on highest compression settings? I can take considerably longer to compress/decompress in that mode, but the file sizes will be somewhat smaller.

Cheers!

[Alex B]

Use some free image viewer like www.irfanview.com and resave your images with somewhat bigger compression setting. Your images seem to be least compressed or some "100% quality" as you might get from Photoshop on highest setting. If you choose IrfanView, go with some 85-90% quality and it will shrink file size multiple times without some visual loss of quality.

[Jarmusch]

Your pics are obviously bigger than the ones from femjoy, so your zip will always be bigger than theirs.

Is it really a problem that your zips are too big? Your members are used to seeing big high resolution pictures one by one, the zip is just a convenient way for them to get an entire photoset on their hard drive without having to save them one by one.

You can always offer your members two zip files for each set: one with the big uncompressed images they're used to and another with downsized and compressed images for a faster download. Give them a choice.

[digifan]

Try the photoshop plugin BEFORE making the zip files, you won't regret it.

[Wetdog]

I have used this in the past with good results:
Ulead Smart Saver 3.0
http://www.ulead.com/ssp/runme.htm