PNG vs. JPG?

[lizajane90]

I recently learned that the "png" file format exists. Can someone tell me how
png differs from jpg and why I'd use one vs. the other in PowerPoint (2003)?
Does it affect file size, usability, or what? Thanks in advance.

 

[TAJ Simmons]

LizaJane90

I've been a big fan of PNG for a long time now.

In short your files will be bigger with PNG than JPG.
Neither format will affect usability/compatibility.

JPG files 'throw away' information.
PNG files do not throw away information.

In most applications when you choose to save a picture as a JPG, somewhere
there is a 'options' page that has a sliding scale for (quality), or (how
much info to throw away).

JPG is clever in that the info it throws away is difficult for the eye to
notice.

For the deep complicated info see

JPG
http://en.wikipedia.org/wiki/JPEG

and PNG
http://en.wikipedia.org/wiki/Png

Cheers
TAJ Simmons
microsoft powerpoint mvp

awesome - powerpoint backgrounds,
http://www.awesomebackgrounds.com
free powerpoint templates, tutorials, hints, tips and more...

 

[lizajane90]

TAJ:
Thanks for the knowledge. Think I'll probably stick with jpg since I'm
looking to get my PPT template as small as possible.
lizajane90

 

[TAJ Simmons]

Lizajane90

Think I'll probably stick with jpg since I'm looking to get my PPT template
as small as possible.

That's probably a good choice - if you keep the 'slider' to high quality
most people cannot tell the difference between a JPG and a PNG

cheers
TAJ

 

[Tim Murray]

I recently learned that the "png" file format exists. Can someone tell me how

png differs from jpg and why I'd use one vs. the other in PowerPoint (2003)?
Does it affect file size, usability, or what? Thanks in advance.

One problem with JPEGs is artifacts -- small spurious dots scattered around
what would otherwise be a solid color, even (and usually) white. You see them
in some logos on corporate web sites. If you look carefully in white areas,
you may see lone colored dots. Another commonly found bad example is the
screen shot.

In summary, JPEGs are good for photos; GIF and PNG for logos and screen
shots.

 

[Charles Radanovich]

you can also use pngs if you have a graphic with a transparent area you want
to 'float' over your powerpoint background, such as a logo.

 

[smiachon]

In short your files will be bigger with PNG than JPG.
Neither format will affect usability/compatibility.

I'm not so sure with this compatibility problems.

Our PPT mac users heavily use the screen copy procedure included in
the mac system (the famous apple-ctrl-4). This used to copy a JPEG
image in the clipboard on previous versions of Mac OS X. Since a
couple of month (one year?), Apple shifted to PNG as the default
format.
As a result, a number of PPT presentations made on mac could not
display images correctly on PCs. It seems the version of Powerpoint PC
might be important.
So I would not say that the change to PNG will not affect
compatibility.

After some problems, we decided to revert the screen copy image format
to JPEG (using the excellent and free ToolsX utility).

But I agree that for printing purposes, the PNG format is better.

Sorry for my approximate English technical terms, as my software is in
French.
Cheers,

 

[Steve Rindsberg]

I'm not so sure with this compatibility problems.

Our PPT mac users heavily use the screen copy procedure included in
the mac system (the famous apple-ctrl-4). This used to copy a JPEG
image in the clipboard on previous versions of Mac OS X. Since a
couple of month (one year?), Apple shifted to PNG as the default
format.
As a result, a number of PPT presentations made on mac could not
display images correctly on PCs.

That doesn't necessarily follow. PNG is one of Windows PPT's native formats.
Pretty much any image in Win PPT is PNG, JPG or GIF (or gets converted to one
of those on import)

It seems the version of Powerpoint PC
might be important.

Really really old versions might have trouble with PNG, but anything since 97
shouldn't.

What kind of problem do you see on PCs when your users use this screen capture
method? It may be that the Mac never attempted to use QT compression on JPGs
(which are heavily compressed already) but does now with PNGs? If so, that
would cause trouble for PCs.

So I would not say that the change to PNG will not affect
compatibility.

After some problems, we decided to revert the screen copy image format
to JPEG (using the excellent and free ToolsX utility).

But I agree that for printing purposes, the PNG format is better.

Sorry for my approximate English technical terms, as my software is in
French.

But your English is perfectly clear. No worries.

Cheers,

================================================
Steve Rindsberg, PPT MVP
PPT FAQ: www.pptfaq.com
PPTools: www.pptools.com
================================================