Rendering PNG Images Using Various FO Tools

[Harry Goldschmitt <harry@hgac.com>]

I've been struggling for almost a week trying to create PDF output 
from fo files with PNG images in them.  I know that fop 0.94 can 
handle certain PNGs, since some of my PNGs and the annotation PNGs 
work.  Unfortunately, many of them don't.  I've also tried fop 
0.95beta1, with similar results.

The PNGs display fine in browsers, when I convert to html, and with 
the ImageMagick display command, XnView and Graphic Convertor on my 
Mac.

The PNGs were generated by various authors, so I can't easily 
recreate them with another tool.  I have been able to create my PDF 
by first converting the PNGs to PDFs using ImageMagick convert and 
then using RenderX's XEP to process the fo.  Unfortunately, the free 
version of XEP stamps the bottom of each page.  I've tried editing 
and saving with XnView.

I've tried converting the PNGs to BMPs, JPGs, GIFs, TIFFs, EPSs and 
SVGs (inkscape).

I'm also trying to use the xfc-42p1 fo2rtf command with similar 
results, except it can't handle PDF files.

What I'd like, ideally, is a canned convert command to process the 
PNGs so they can be handled by both fop and fo2rtf.

I've tried assorted convert commands like

convert -flatten

with no luck.

I've also tried comparing PNGs fop is having problems with to those 
that it doesn't using identify and pngcheck.  There are differences, 
but when I try to use convert to fix them it doesn't seem to help.

Harry