A Photography forum. PhotoBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » PhotoBanter.com forum » Digital Photography » Digital Photography
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

File size saving for web



 
 
Thread Tools Display Modes
  #1  
Old January 7th 05, 12:12 AM
paul
external usenet poster
 
Posts: n/a
Default File size saving for web

I noticed irfanview creates way smaller files when batch reducing & did
a little test with some different programs. The most obvious thing is
that saving with photoshop preserves the exif info and thumbnail adding
about 13KB to the file size unless you use the save for web route.

All these were done at mid range quality 50% for the same 640x425 image.


In order of file size:
60KB Photoshop saveas
47KB Photoshop saveas after stripping EXIF info with exifer
37KB Photoshop save-for-web
35KB ThumbsPlus 1:1 sub-sampling
26KB ThumbsPlus 2:2 sub-sampling
24KB ThumbsPlus 4:2 sub-sampling
20KB Irfanview

That's a huge spread!

I didn't try the ThumbsPlus smoothing, I assume that's the same as
photoshop save-for-web blur which reduces file size.

Irfanview cut one pixel off in the resize producing 640x425 (not 426).

Photoshop save-for-web is nice because you see the before-after & it
helps to zoom in to 400% to see the effect. When I scrolled through
these samples I could only tell the irfanview file was missing fine
detail, normally large simple areas like the sky get posterized & that's
the ugliest effect, in those cases it's probably a small file anyways
since it's simple so you can use a higher quality.

I normally use about 60% to 70% & shoot for well under 100KB for a
640x425 image but now I'm going to have to remember never to use
photoshop without the save-for-web thing & use a higher setting if I'm
batching with Irfanview.

Most web designers try to make web general page images no more than 20KB
& that's almost the size of the EXIF info alone so I would definitely
think twice about including that. There are programs for exporting EXIF
into a text file & it would be worth taking such an approach in
designing a web site for photography.

I understand photographers are going to want a nice big picture so 20KB
is asking a lot but I've seen some awesome portfolios with tiny 300pixel
wide images that look spectacular so it's good to just remember that
it's not always necessary to make big files. People lose patience
quickly waiting for images to load, even a mediocre DSL line takes a
while to load a 120KB image when half that size would probably do.

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Newbie: file size after editing . ABC Digital Photography 8 March 3rd 05 07:30 PM
Pentax RAW file size [email protected] Digital Photography 24 January 6th 05 09:12 PM
Question about RAW file and image size Anynomus Digital Photography 9 November 7th 04 10:51 PM
Reducing File Size / Sharing Photos / Album Help Dave Digital Photography 10 September 16th 04 10:36 PM
ISO and File Size Question David J Taylor Digital Photography 7 July 15th 04 12:50 AM


All times are GMT +1. The time now is 06:27 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 PhotoBanter.com.
The comments are property of their posters.