How can I create a 32-bit PNG?

Question

I've been researching ways (PHP, JavaScript, etc.) to make alpha-transparency work with PNGs in Internet Explorer 5.5+ and I came across one method but it said: "This only works with 32 bit PNGs. 24 bit PNGs contain no alpha info and IE incorrectly displays 8 bit PNGs with alpha." (I thought this was incorrect but, hey, who am I to question the content of a page on the Internet?) Anyhoo, I'm using Photoshop CS2 and I can only export to PNG 24-bit and PNG 8-bit. What program do I use to create a 32-bit PNG?

Source: http://www.mongus.net/pngInfo/

Answer 1

The trasparency in the GIF image is not based on alpha values, but on a color that will be used as a transparent color (i.e, the pixels in that color will not show when the image is rendered).



The color in a 32 bit per pixel image is formatted as ARGB (alpha, red, green, blue)

Each compoment of the color is a 8 bits value.



A 24 bits PNG only contain RGB values (there is no alpha information to make transparency or alpha blending)



I don't know much about Photoshop CS2, but I would be surprised if there wasn't an option to import the Aplha value..maybe you need to import that as a layer and then combine the RGB layer with the Aplha layer and then save the image as a 32 bits PNGs



I have used Paintshop Pro, and it can read 32 bits PNG without any problems.

Answer 2

32 Bit Png

Answer 3

First you need to have a computer capable of running it, don't forget vista's heavy and drags even a good computer. And unless they provide you the component drivers for the 64 windows, the standart ones are the 32. Without proper drivers you'll have major communication issues between the machine's components. Unless your in a field that requires extensive use of the computer (archicad, autocad or photoshop) you won't see much difference even if you have the proper drivers installed.

Answer 4

As far as I know, transparency can only be achieved using the GIF format. You could try converting the PNG to GIF and then setting the transparent layer. This will definitely work if you have transparency set up in the GIF.