- for cartoonish images, images with 2 or more full colors like logos, icons like arrows, questionmarks
- semi transparent images (with or without matting) but never shadows which looks awfull

JPEGS
- all photographic images (thousands, millions of colors)
- images which have shadows and /or gradients tend to look better in comparison with saving them as GIFS

PNG-8

- like GIF but has a lot of probs with compressing and saving, especially Safari (Gamma) and IE WIN with color tables
here is a good link which explains all flaws with PNGs
<http://hsivonen.iki.fi/png-gamma/>

PNG-24

alpha channel transparency, below IE7 WIN does not work, big file sizes?

Johan said on August 30, 2006

link about probs with saving for web as PNG

Olly said on August 30, 2006

I thought the colour difference thing was down to a slight difference of opinion between IE and Photoshop, but it appears that IE gets it wrong even though the PS bug has been fixed. PNG color oddities in IE has more on the sybject (esp. in the comments).

Jonathan Snook said on August 30, 2006

8bit PNG beats 8bit GIF hands down almost every time (but not always). As many have mentioned, IE has gamma issues with PNG's (as can be seen by the nav on www.wowgoldme.com in IE).

24bit PNG vs JPG for things like gradients can be a toss-up. If the image is large, I usually have to go JPG. If it's small to medium, or has sharp edges (eg: along text) then PNG is often the way to go.

Andy Kant said on August 30, 2006

I use PNG unless I have problems with the gamma in IE (didn't know there was a fix until I read some of the other posts), then I use GIF. I limit most of my images to 8bit to save on filesize. I only use JPG for photos.

Sam said on August 30, 2006

Same here, I use GIF for the small images, logos, backgrounds. JPG should be used for the photos and images with full color scheme. Had the same experience with PNG in IE.

Martin said on August 30, 2006

There's only one reason for still using GIF's, the transparency issue in Internet Explorer

I disagree. PNG also supports binary transparency as GIF does. For me, the only reason would be animation.

I use PNG unless I have problems with the gamma in IE [...], then I use GIF

I didn't know this problem, but you could try to save the PNG without gamma information.

For maximum compression, I suggest optimizing the images with tools like PNGOUT.

Martin said on August 31, 2006

I verified that removing the gamma information solves the problem with darker images in IE. No reason to use GIF for non-animated images anymore :)

pawel said on August 31, 2006

If you are not using alpha transparency (...) then exporting as an 8-bit PNG is the way to go.

It's possible to create 8-bit PNG with alpha transparency.
Photoshop 7 (and probably newer versions - I'm not sure) doesn't support 8-bit png with alpha, so I export to PNG-24 and then use command line pngquant that reduces image to 8-bit palette.
(examples)

Justin Makeig said on August 31, 2006

I use pngcrush to compress and, more importantly, remove the gamma information from PNG images saved from Photoshop.

Here’s the rudimentary shell script that I use to do the “crushing”. (It only replaces the file if it’s actually changed.)

#!/bin/sh
#
# Uses pngcrush to crush a given PNG file and remove the gamma.
# Only replaces the file if it was actually changed.
#
if [ -z $1 ]; then
	echo "Usage: ./crush.sh myfile.png"
	exit 2
fi
export CHECKSUM="`md5 -q $1`"
export TMP=".TMP"
export TMPIMG=$1$TMP
pngcrush -rem gAMA $1 $TMPIMG
export NEWSUM="`md5 -q $TMPIMG`"
if [ $CHECKSUM != $NEWSUM ]; then
    cp $TMPIMG $1
    echo "$1 was sucessfully crushed"
else
    echo "$1 was untouched"
fi
rm $TMPIMG
Erick Schluter said on September 09, 2006

Got it bookmarked for future reference! Allthough the differences where known to me, it's always nice to have it nicely written down. Great!

Wolter Hellmund said on April 07, 2007

I think that your blog has a very nice and clean style. I like the date stamp on the left top part.

The information you have was just what i was looking for.

Steve said on September 30, 2008

Surely the best way to avoid IE's issues with PNG is just not to use IE? Firefox is superior in every way (not least security and standards compliance) anyway.

Sorry, comments are closed for this post. If you have any further questions or comments, feel free to send them to me directly.
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