Converting ico files to other format many output files are created, why?

Dear all,

I have a question. When I use imagemagik  (Version: ImageMagick 6.6.3)
to convert ico files to other image formats I obtain many output files,
not a unique output file, for example:

convert fb.ico fb.png

it produces these 5 output files:


fb-1.png
fb-2.png
fb-3.png
fb-4.png
fb-5.png
fb-6.png
fb-7.png
fb-8.png
fb-9.png


it seems all the same image but they are different, somebody know what
is the difference? I have tried googling, but I have no find useful results.

Thanks


Sandro




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