convert fails for pngalpha device using new ghostscript

When converting ps or eps files among each other or to other
image formats you get an error message (version 6.3.8-2 and -0 and -1
under Fedora 8):
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$ convert -verbose fig3.eps fig3.png
"gs" -q -dQUIET -dPARANOIDSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=0 "-sDEVICE=pngalpha" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-r72x72" -g573x489  "-sOutputFile=/tmp/magick-XXnkS3SE" "-f/tmp/magick-XXDo5ydB" "-f/tmp/magick-XXoGJcyx"
convert: image size exceeds user limits in IHDR `/tmp/magick-XXnkS3SE'.
convert: Corrupt image `/tmp/magick-XXnkS3SE'.
convert: Postscript delegate failed `fig3.eps': No such file or directory.
convert: missing an image filename `fig3.png'.
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This seems to be due to the use of pngalpha device. I patched the source changing pngalpha
to pnmraw and that fixed the problem:
=======================================
$ convert -verbose fig3.eps fig3.png
"gs" -q -dQUIET -dPARANOIDSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=0 "-sDEVICE=pnmraw" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-r72x72" -g573x489  "-sOutputFile=/tmp/magick-XXLe779y" "-f/tmp/magick-XXCn6BBc" "-f/tmp/magick-XXQWJe3P"
/tmp/magick-XXLe779y PNM 573x489 573x489+0+0 DirectClass 8-bit 820.971kb
fig3.eps PS 573x489 573x489+0+0 DirectClass 16-bit 820.971kb
fig3.eps=>fig3.png PS 573x489 573x489+0+0 DirectClass 16-bit 33.4922kb
=======================================

I am not sure whose fault this is, ImageMagick or ghostscript, please advise!
Thanks