beginner question

[Shadowkiller]

I think you will find that knocking down the files size from 2-3meg to 100k for posting on this forum will seriously reduce the quality of any pic.

If the pic has few colours, and strong contrast the file size will be smaller initially and quality will stay higher, but a more complex image like F81 posted will suffer from the compression algorithm.

 

[loopy]

Hey sash, long time no talk - sent you a bunch of sms but you rarely use your phone ya cheeky bugger Send me an email - bradley.drew at defence.gov.au cause I've lost yours

Disagree on the first bit - use anything past about photoshop 6, and then select "save for web"... i can save a 2000x3000 pic (ie 6MP) at "low" res (file size about 100k) and it still looks really good. Admittedly though, that's pretty much the only prog I've seen that resizes well.


Cheers,

Brad

 

[Shadowkiller]

Hey Brad,

Things depend a lot on the pic. After editing over 2000 photos in the last year, I can tell you for dead cert that no compression algorithm is good enough to keep the quality the same when going from 5meg to 100k. Simplistic pics, monochrome especially, do ok, but intricate detail photos, especially with a colourful background, suffer. Edge pixilation is particularly bad, no matter what compression I use in PS7.

Also: My old mobile fell off a crane, so i have a new one. I got your email titled "Hey Dad" so you do still have my email, exams prevent me from replying to the 120 odd emails I got in the last week...

 

[loopy]

Wow, I've been smacked! :ban



I tried it out last night though - I have 4682 images from my D70 (taken since April), all at 6 megapixel res (file size is on average about 2-3 meg, depending on colours)... I picked randomly about three dozen pics (with varying numbers of colours/colour distributions) and compressed them. I might have not mentioned before, but I'm including shrinking (from 3000x2000 down to 1800x1200) and applying "medium" compression - all the file sizes were sub 200k, and to look at the original compared to the copy, yeah sure you could tell a few minor diffs, and you've got virtually no zoom quality but stand back a bit and for all intensive purposes its the same pic. I tried fiddling with the compression settings under "Save as" and couldn't get anywhere near the same compression rates while still keeping reasonable quality. I'll try to get a few pics off my comp sent over here to show (takes a while because this computer has no floppy/usb access, so I have to email from a public computer... )

 

[Adrian]

Brad,
If you can get a hold of one of the PhotoImpact programs, even if it's an older version they have an excellent jpg compression where you can see exactly what you get while comparing it to the original at different compression settings before saving the file. You can download free trial that lasts a month at www.ulead.com

Here's a more specific link, its called Smart Saver Pro as a stand alone, but a similar version is incorporated into the PhotoImpact series all the way back to PhotoImpact 3 I believe.

http://www.ulead.com/ssp/runme.htm

Adrian