4

I recently discovered something that I previous thought was impossible: PNG-8 files can store Alpha Transparency in the same way as PNG-32 files can. Not Indexed Transparency (like GIFs), but full on Alpha Transparency.

(You can learn more about this here: http://blogs.sitepoint.com/png8-the-clear-winner)

Apparently it's possible to do this using Fireworks, but I can't find a way to do it using Photoshop.

Does anyone know a way of enabling this incredible feature in Photoshop? Through add-ons or by any other means? It's so incredibly useful for web developers that I can't believe it's not been included in the latest version (or any version) of PS!

  • 3
    Photoshop and PNG-8 hate each other. Just thought you should know. – Ignacio Vazquez-Abrams May 17 '11 at 21:00
  • @Ignacio: lol :) – user541686 May 21 '11 at 7:41
3

An updated answer for 2015 tech.

I'm using Photoshop Creative Cloud 2015 (for PC, I don't know if there is any difference on Mac) and there is a choice to

"File > Export > Export as"

There aren't a whole lot of options to adjust from here, but if you select PNG-8 format it will automatically use full (or what appears to be full) alpha transparency in a PNG-8 format. Mileage may vary depending on image size and number of colors as to whether or not the result will actually be smaller than a regular PNG-24. On average the images I have been working with have resulted in about 1/3 final file size when compared to a PNG-24 of the same image.

NOTE: Check that the image mode is NOT indexed (lock icon on the layer) as I was not able to get the alpha transparency to work otherwise. I used RGB mode with successful results.

  • Yes, it's far from perfect (and seems slower), but it's sort of there. I hope Adobe finally improves this soon. – Django Reinhardt Aug 10 '15 at 12:06
2

Not that I know of, but save the image as PNG-24 then use this:

http://compresspng.com

(I tried http://www.8bitalpha.com and http://tinypng.org but they gave me poor results.)

  • Seems a lot slower than 8bitalpha and tinypng, but good for control, thanks. – Django Reinhardt Oct 3 '13 at 16:42
1

You can use Ethan Gardner's pngquant script to convert a photoshop file to alpha-tx PNG. It works on Mac and PC. http://www.ethangardner.com/articles/alpha-transparency-in-png-8-images-without-using-fireworks/

  • This may be the best option available today. Such a shame, but thanks. – Django Reinhardt Oct 3 '11 at 0:31
1

This is an important subject, especially for web design. A big png24 image can be ~1mb, almost impossible to consider for web site design use. But same image as png8 with alpha is ~250kb, ok in a lot of situations.

And finally a drag-and-drop solution for png8 with alpha transparency, free as of 2013 04: http://tinypng.org/

And some more related tools are here: http://pngquant.org/

Enjoy!

0

If you're on a Mac, you can use the excellent (and free) ImageAlpha tool to do this to a PNG-32 using a GUI, live preview, etc.

-3

go to file > save for web and device

look at right side there is a drop down after Preset you'll find there PNG 8 there are some option related to transparency,just check them out.

  • 1
    Yes. Those options are for indexed transparency. My question was about alpha transparency. – Django Reinhardt May 23 '11 at 0:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.