icc profile conversion and always growing file

Hi there,

I've found an interesting behavior of imagemagick and need an explanation why this happens:

First I've made some image files:

1) C:\FGE-AR-BW\test>convert ARsw-676b.tif -profile C:\WINDOWS\system32\spool\drivers\color\AdobeRGB1998.icc -quality 100 -compress lossless ARsw-adobergb.jpg

2) C:\FGE-AR-BW\test>convert ARsw-676b.tif -profile C:\WINDOWS\system32\spool\drivers\color\sRGB_Color_Space_Profile.icm -quality 100 -compress lossless ARsw-srgb.jpg

3) C:\FGE-AR-BW\test>convert ARsw-676b.tif -quality 100 -compress lossless ARsw-ohneprofil.jpg

4) C:\FGE-AR-BW\test>convert ARsw-ohneprofil.jpg -profile C:\WINDOWS\system32\spool\drivers\color\AdobeRGB1998.icc -quality 100 -compress lossless ARsw-nix2adbrgb.jpg


The file sizes are:
27.02.2008 10:37 2.362.258 ARsw-676b.tif

1) 27.02.2008 10:40 533.295 ARsw-adobergb.jpg

2) 27.02.2008 10:42 535.879 ARsw-srgb.jpg

3) 27.02.2008 11:07 532.717 ARsw-ohneprofil.jpg

4) 556.730 ARsw-nix2adbrgb.jpg


If a now perform an "intrafile" icc profile conversion the file size is much bigger than is should be. Please eplain me why:

C:\FGE-AR-BW\test>convert ARsw-adobergb.jpg -profile C:\WINDOWS\system32\spool\drivers\color\AdobeRGB1998.icc -profile C:\WINDOWS\system32\spool\drivers\color\sRGB_Color_Space_Profile.icm -quality 100 -compress lossless ARsw-adbrgb2srgb.jpg
file size:
27.02.2008 10:45 705.466 ARsw-adbrgb2srgb.jpg

In this example above I've expected a file size like 2) !

As a second check I tried an icc profile conversion with exiftool and the resulting file size, is the one I've expected:

C:\FGE-AR-BW\test>exiftool "-ICC_Profile<=C:\WINDOWS\system32\spool\drivers\color\AdobeRGB1998.icc" ARsw-ohneprofil.jpg (the resulting file was renamed to ARsw-nix2adbrgb-exiftool.jpg)

file size:
532.717 ARsw-ohneprofil.jpg
533.295 ARsw-nix2adbrgb-exiftool.jpg

by the way the icc profile size is:
AdobeRGB; profile-icc: 560 bytes
sRGB; profile-icc: 3144 bytes


regards,

Frank