png8 with alpha transparency in X8

[flagpole]

Anyone know if the png optimiser now supports alpha transparency with the 8 bit colour pallet?

In x6 you can only have alpha transparency with full 24 bit colour.

[LeviFiction]

I'll admit I haven't used X6 in a while but I could have sworn the PNG optimizer had a "Palette-Based" option for the image type.

In X8, the PNG optimizer lets you use either a Palette Based, Greyscale, or True Color image type. The Transparency tab has options for identifying a single color as the transparent area. Or using the current layer transparency to create the transparent areas.

So, unless I'm misunderstanding. Yes, X8 does allow you to save an 8-bit greyscale or 8-bit 256 paletted image with transparency using the PNG Optimizer.

[flagpole]

OK, clarify.

X6 does not do what I'm after. I want to know if you can have pallet based colour with full alpha channel transparency. So in X6 you can have full colour and full transparency but if you drop to pallet based colour you can only have single transparency (as in 100% transparency or not,) not variable transparency.

So see here i have pallet based colour selected and alpha channel transparency is greyed out:

You may think i'm being pedantic but it makes a difference. If your images are not 'optimised' on a website it comes up in the google speed report which apart from being a nag can affect your rankings.

[LeviFiction]

Then no. X8 has exactly the same options as X6.

While I'm not surprised PSP doesn't keep up with things like this. I was surprised to learn many applications don't directly support it. Photoshop CC only recently got this option.

What do you normally use? I wonder if a script could be developed that used the TinyPNG web service to get the same effect until PSP got support for it.

[flagpole]

tinypng have a PS plugin, i don't know if that could be used. I'm not paying the $50 to find out.

When google starts moaning it points you here:
https://developers.google.com/web/funda ... ter-tuning

so tiny png is an online implementation of a tool called pngquant. there is a PS plugin for that too called SuperPNG which has an 8bi extension. don't know if it's supposed to work with PSP but i can't get it too.

as for me i use either tinypng or pngyu which is a nice gui. But it would be nice to be able to see changes you make to your images and the effect on size in a more direct way.

incidentally the saving on the site in my signature is 65%, which is like 20GB a month saving.

of course you can't really load png8 with alpha transparency back in to psp, that would be a start.

^ PNG8 29KB

^ PNG24 99KB

how about that? if you load them in to X8 do they look similar? or as in X6 where the partial transparency id lost?

[LeviFiction]

Transparency is also lost in x8.

8bi is a file format plugin so it shows up when saving or opening files. In this case saving them. It does show up in the list as SuperPNG. Using it is a little wonky though. Don't know if it works in X6 but it does work in x8.

PSP forces you to merge the document to a single layer destroying all of the transparency if you choose SuperPNG from the list. So, to get what you want you have to save the transparency to an alpha channel first. Then run the save to SuperPNG.

Fastest method I know to do this.

1) Select All
2) float selection
3) Delete floating layer
4) Save Selection to Alpha Channel

Easily scripted. Though it only works if the image is a single layer so you would have to merge visible before running the script just to be sure.

It does not have a preview or a new size information though. It's only more direct from PSP.

[flagpole]

thanks levi, that's useful information.