PNG instead of GIFs

[shiphen]

I just read on a webmaster's forum that PNG files appear to give much better compression that GIFs. (4 to 40% smaller files). Can anyone confirm this?
Should we all start moving over to PNG?!

The only problem seeming was NN4 which doesnt like them, and their apparent lack of transparency.

Any views?


Ship
Shiperton Henethe

P.S. What exactly ARE "PNG" files?!
They're bitmaps too right, not vectors?

[shiphen]

I just read on a webmaster's forum that PNG files appear to give much better compression that GIFs. (4 to 40% smaller files). Can anyone confirm this?
Should we all start moving over to PNG?!

The only problem seeming was NN4 which doesnt like them, and their apparent lack of transparency.

Any views?


Ship
Shiperton Henethe

P.S. What exactly ARE "PNG" files?!
They're bitmaps too right, not vectors?

[Toby]

I think PNGs are raster images, but XaraX treats them on import as vectors (is that right - that's how it seems...).

I don't think IE6 supports PNGs aplha transparency either, which is why it isn't becoming the standard for the web just yet - no doubt it will at some point though, just as soon as you can animate them... http://www.talkgraphics.com/images/smilies/biggrin.gif

Correct me if I'm wrong. Which I often am.

Tobyboy.

[qmr]

Ive always thought of pngs as raster images, but Fireworks uses png as its format for vector drawings as well.
Personally Ive found png to be useless for web bitmap images as Ive never figured out the compression settings, whereas gifs are simple. And Im too imaptient to read more. Jpegs can be compact and sharp so what the hell.
I use png as a storage format for shifting a bitmap between editing programs etc.
The only format that excites me any more is swf. But overlapping transparent swfs might be a thing of the past if microsoft stop using activeX. sigh.
Q

[gwpriester]

The confusion is Macromedia calls the files it creates in Fireworks PNG files.

But 8-bit, 24-bit and 32-bit PGN files are bitmaps, not vectors.

WMF and EMF are vector formats that also can contain bitmaps.

Gary

Gary Priester

Moderator Person


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www.gwpriester.com </a>


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[Charles Moir]

PNGs are great and are designed specifically to replace GIFs (they are bitmaps like GIFs, not vector). Pretty much anywhere you use a GIF you are better off using a PNG. They are smaller (better compression) and are a patent free, and support better quality images (24-bit and 32-bit) images which GIFs do not.

It's true that really old browsers (used by less than 1% of users) do not support PNGs, but all modern browsers support them to at least the level of GIFs.

PNGs have only two drawbacks:
a) They cannot be animated like GIFs
b) The PNG standard supports true 32-bit alpha-channel images (16 million colours plus 256 levels of transparency) which GIFs cannot get close to. This would be truly great but for the fact that Microsoft Internet Explorer doesn't work properly with alpha-channel PNGs (Mozilla and all other major browsers do correctly support alpha-channel PNGs)

Of course (b) is not really a drawback of PNGs, but a drawback of IE.

You can directly compare the quality and compression of GIFs and PNGs in the Xara X export dialog. Select an image to export as GIF and then in the preview dialog, you can select GIF for the left side preview and PNG for the right side window and then vary the number of colours and other factors. PNGs are nearly always better than GIFs - sometimes even as much as 40% but not usually that much.

They are the best form of bitmap export and import from and into Xara X becuase Xara X does fully support alpha channel transparency and so in this respect they are better than TIFFs for many applications (and offer better compression than TIFFs).

A really good demonstration of the capabilities of PNGs is to save a simple soft shadowed object from Xara X as a 32-bit PNG, and then load this into any program that fully supports alpha channel PNGs (such as Mozilla). You can now place the image over any background and the object remains fully anti-aliased no matter what background colour or texture, and the soft shadow works exactly as you'd expect on any background. You can't do that with a GIF.

Charles