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I recieved a couple of Fireworks PNG files. Fireworks has a special format for saving several source images in layers in the png file.

How can I read these without having Fireworks installed?

(im working on a mac but with vmware so any suggestions whatever platform is appreciated)

EDIT: I'd prefer to get a set of copies out of of the layered png. And I prefer if the export be lossless

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migrated from stackoverflow.com Oct 2 '09 at 15:00

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4 Answers

up vote 10 down vote accepted

PNG files do not have layers, so Fireworks layers are stored in the private chunks of the PNG files in a proprietary format which is not PNG. I don't know of any program that can read them. You'll need to ask the owner of these photos to convert them to flattened png (mono-layer) or into another multi-layered format such as psd.

If that's not an option, my only advice is to download a trial version of Adobe Fireworks (registration required) to convert these photos.

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+1. But one clarification: It's the actual contents format of the anciliary chunks used to store multi-layer information that is not understood by other tools. There's nothing non-PNG in using these chunks. They are described in the PNG specification (w3.org/TR/PNG/#11Ancillary-chunks). APNG is backwards compatible with PNG and fireworks doesn't normally break that (to my knowledge). APNG is simply an unnoficial extension, not another type of PNG. –  A Dwarf Oct 2 '09 at 21:51
    
+1. very annoying that I actually ended up installing a trial of Fireworks to read the layers of the file –  Jesper Rønn-Jensen Oct 5 '09 at 10:44
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Well, if you just need to read these files you can use Batch PNG to JPG to flatten them. It includes a Preview which allows you to actually look at the PNGs if that's just what you want. But if it is animated it will only export the first frame.

So,

XnView viewer, fully supports APNG
Firefox browser, too
ImageJ image processor, too

Meanwhile I noticed you came from Stackoverflow.com. If you need to programmatically access this format, you will need a patch for libpng that gives you support for APNG. It's an excellent (albeit, slightly non-standard) addition to libpng if you need it. It's after all what all the above applications use. ;)

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Good, comprehensive answer. I didn't know Fireworks used APNG format, that's better than being totally proprietary... On another site, somebody asked how to /repair/ such file that Fireworks is no longer able to load (or at least salvage as much as possible). If you have an idea... :-) –  PhiLho Oct 2 '09 at 15:55
    
Hmm... if fireworks is no longer able to load such a file, then it must be corrupt. There's a possibility it was made with another tool like ImageJ above. So it could pay to try and load it from there. If it fails the only way is exactly to fire up a good Hex editor and follow the APNG specification (wiki.mozilla.org/APNG_Specification) to see what's wrong. 010 Editor (sweetscape.com/010editor) supports binary templates. You can create your own or use aleady made ones which already include templates to parse PNG and PNG chunks. –  A Dwarf Oct 2 '09 at 16:28
    
Very comprehensive, but i have not marked as answered yet because of one thing: What I really want is to get the layers out as pngs. (it has to be lossless). I'm editing the question to reflect it. –  Jesper Rønn-Jensen Oct 2 '09 at 18:04
    
ImageJ which I just tried out can read only the file but see only the top layer. I can't see the other layers. So ImageJ can't solve my problem –  Jesper Rønn-Jensen Oct 2 '09 at 19:16
    
You are rapidly approaching the limit of my knowledge about this issue. I'm not experienced with it. Just so happens recently I had to do some work involving APNGs. Try and see if you can get the layers to show with Evan's Image Editor (evanolds.com/eie.html). If that fails, you really need to use an hex editor. You will want to look for text chunks (w3.org/TR/PNG/#11textinfo). Hopefully they may contain information about what software made the file. –  A Dwarf Oct 2 '09 at 19:41
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The only programs I've seen apart from Fireworks that preserved those PNG layers were Freehand and Flash (both are ex-Macromedia). The last time I did that was a few years ago so I'm not even sure if the current versions retain that capability.

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You can save from any Adobe Fireworks you have at your disposal, and save with a GIMP .psd and so can at least detect the layers of your archive.

You can move objects and text layers, but with text layers you cannot modify the text and keep the same format, only by deleting and doing it using the GIMP text tool .

I am using Adobe Fireworks CS5 and Gimp 2.4.0 for testing.

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