I thought there is only PNG8 and png32, but photoshop has option for PNG24, and fireworks has all 3 options. Which is better for web world?
Also when I export PNG24 with alpha transparency in fireworks, it always adds background color, but in photoshop, it exports with alpha .
"Also when I export PNG24 with alpha transparency in fireworks, it always adds background color, but in photoshop, it exports with alpha ."
You need a PNG32 for the alpha channel, so when you save a PNG24 with an alpha channel, PhotoShop actually makes it a PNG32.
In Fireworks, it actually let's you manually make the decision, so if you choose PNG24, you lose the alpha channel in the process.