Copyright of a costumized pixel map image

[Mats Erik Andersson <mats.andersson@gisladisker.se>]

Dear all,

I could use a pointer on the best mode of describing a copyright
attribution. In my package "rgbpaint" I use a suitable XPM image,
existing in the upstream source archive, and with a modified build
system it is installed in '/usr/share/pixmaps/' as the program
icon of choice for the final binary package.

Now I have discovered that the background is black, so I would like
to modify this image by making it into a PNG image with transparent
background. This in order to blend better for desktop usage.

If I, in the package source, leave the script snippet for imple-
menting this format change, as well as the new transformed image,
will it be sufficient to attribute a copyright claim on the new picture
to the author of the original picture, or is some composite copyright
attribution mandatory in this situation?


Best regards,
  Mats Erik Andersson, DM