PNGs alpha transparancy in AS3 - Unknown file-type

Question

Hello there!

After whittling down of the options we've encountered a problem with PNG's and ActionScript 3 (AS3).

When loading a PNG 8 or PNG 32 with alpha transparancy we're getting the following error reported in Flash:-

"Error #2124: Loaded file is an unknown type"

Now, we're dealing with some legacy images, and it appears as though this problem isn't universal - some images believed to be 32bit alpha PNG are loading. BUT, some conclusions:-

• converting one image that was 32 bit alpha (NOT WORKING IN AS3) to PNG 8 index transparency DID work.
• And converting that same image to PNG 8 alpha DID NOT work.
• These all worked in AS2
• There is no difference between the headers

Headers of a Failing Image

[0] => HTTP/1.1 200 OK
[1] => Date: Tue, 06 Apr 2010 14:17:28 GMT
[2] => Server: Apache/2.2.3 (Red Hat)
[3] => Last-Modified: Tue, 06 Apr 2010 13:44:05 GMT
[4] => ETag: "3700054-11d6-a3983340"
[5] => Accept-Ranges: bytes
[6] => Content-Length: 4566
[7] => Connection: close
[8] => Content-Type: image/png

Headers of a Working Image

[0] => HTTP/1.1 200 OK
[1] => Date: Tue, 06 Apr 2010 14:19:02 GMT
[2] => Server: Apache/2.2.3 (Red Hat)
[3] => Last-Modified: Fri, 30 Oct 2009 18:38:08 GMT
[4] => ETag: "ba8057-65f2-5445c400"
[5] => Accept-Ranges: bytes
[6] => Content-Length: 26098
[7] => Connection: close
[8] => Content-Type: image/png

Any thoughts of a direction of further investigation or thoughts on a bewildering problem with little to no documentation; very warmly welcomed.

EDIT

Now it would appear as though something in the PHP conversion of the images is shafting; I use the following PHP to add alpha layers:-

imagealphablending($image_p, false);
ImageSaveAlpha($image_p, true);
ImageFill($image_p, 0, 0, IMG_COLOR_TRANSPARENT); 

Answer 1

HTTP headers actually matter only little to flash player. It usually looks at file headers, so you should look whether those are correct. Also, what happens if you take a graphics software, open it and export it again, with 32 bit transparency. Does the problem disappear?

Last but not least, you should consider Flash Player doesn't support all PNG features. The one which people usually run into is interlacing. could that be it?

greetz
back2dos