I likely am misunderstanding this question, but:
. You can use the .INF approach to push registry changes through group policy. There are easier ways to push registry changes, fortunately. See:
. You should know that the easiest way to handle this installation is when Paint Shop is installed. One of the installation options is to assign file extension associations. Also, after installation, the File, Preferences menu allow these associations to be edited and changed.
. Finally, you could use regedit to export the keys of interest to a .reg file, and "push" these changes as discussed in the article linked earlier. To give you a feel for this, these are the registry values for jpg, jpe, and jpeg by default:
[HKEY_CLASSES_ROOT\.jpe]
"PerceivedType"="image"
@="jpegfile"
"Content Type"="image/jpeg"
[HKEY_CLASSES_ROOT\.jpe\OpenWithProgids]
"jpegfile"=hex(0):
[HKEY_CLASSES_ROOT\.jpe\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"
[HKEY_CLASSES_ROOT\.jpeg]
"PerceivedType"="image"
@="jpegfile"
"Content Type"="image/jpeg"
[HKEY_CLASSES_ROOT\.jpeg\jpegfile]
[HKEY_CLASSES_ROOT\.jpeg\jpegfile\ShellNew]
[HKEY_CLASSES_ROOT\.jpeg\OpenWithProgids]
"jpegfile"=hex(0):
[HKEY_CLASSES_ROOT\.jpeg\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"
[HKEY_CLASSES_ROOT\.jpg]
"PerceivedType"="image"
@="jpegfile"
"Content Type"="image/jpeg"
[HKEY_CLASSES_ROOT\.jpg\jpegfile]
[HKEY_CLASSES_ROOT\.jpg\jpegfile\ShellNew]
[HKEY_CLASSES_ROOT\.jpg\OpenWithProgids]
"jpegfile"=hex(0):
[HKEY_CLASSES_ROOT\.jpg\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"
[HKEY_CLASSES_ROOT\jpegfile]
@="JPEG Image"
"EditFlags"=dword:00010000
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52, 00,6f,00,6f,00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00, 32,00,5c,00,73,00,68,00,69,00,6d,00,67,00,76,00,77,00,2e,00,64,00,6c,00,6c, 00,2c,00,2d,00,33,00,30,00,33,00,00,00
"ImageOptionFlags"=dword:00000003
[HKEY_CLASSES_ROOT\jpegfile\CLSID]
@="{11943940-36DE-11CF-953E-00C0A84029E9}"
[HKEY_CLASSES_ROOT\jpegfile\DefaultIcon]
@="C:\\WINDOWS\\Installer\\{90280409-6000-11D3-8CFE-0050048383C9}\\PEicons.exe,5"
[HKEY_CLASSES_ROOT\jpegfile\shell]
[HKEY_CLASSES_ROOT\jpegfile\shell\Open]
@="&Open"
[HKEY_CLASSES_ROOT\jpegfile\shell\Open\command]
@="\"C:\\Program Files\\Common Files\\Microsoft Shared\\PhotoEd\\PHOTOED.EXE\" \"%1\""
"command"=hex(7):43,00,38,00,34,00,44,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 59,00,52,00,5d,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,50,00,68,00,6f, 00,74,00,6f,00,45,00,64,00,69,00,74,00,6f,00,72,00,46,00,69,00,6c,00,65,00, 73,00,3e,00,44,00,6f,00,54,00,5d,00,6a,00,49,00,7b,00,6a,00,66,00,28,00,3d, 00,31,00,26,00,4c,00,5b,00,2d,00,38,00,31,00,2d,00,5d,00,20,00,22,00,25,00, 31,00,22,00,00,00,00,00
[HKEY_CLASSES_ROOT\jpegfile\shell\Print]
@="&Print"
[HKEY_CLASSES_ROOT\jpegfile\shell\Print\command]
@="\"C:\\Program Files\\Common Files\\Microsoft Shared\\PhotoEd\\PHOTOED.EXE\" /p \"%1\""
"command"=hex(7):43,00,38,00,34,00,44,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 59,00,52,00,5d,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,50,00,68,00,6f, 00,74,00,6f,00,45,00,64,00,69,00,74,00,6f,00,72,00,46,00,69,00,6c,00,65,00, 73,00,3e,00,44,00,6f,00,54,00,5d,00,6a,00,49,00,7b,00,6a,00,66,00,28,00,3d, 00,31,00,26,00,4c,00,5b,00,2d,00,38,00,31,00,2d,00,5d,00,20,00,2f,00,70,00, 20,00,22,00,25,00,31,00,22,00,00,00,00,00
[HKEY_CLASSES_ROOT\jpegfile\shell\Printto]
[HKEY_CLASSES_ROOT\jpegfile\shell\Printto\command]
@="\"C:\\Program Files\\Common Files\\Microsoft Shared\\PhotoEd\\PHOTOED.EXE\" /pt \"%1\" \"%2\" \"%3\" \"%4\""
"command"=hex(7):43,00,38,00,34,00,44,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 59,00,52,00,5d,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,50,00,68,00,6f, 00,74,00,6f,00,45,00,64,00,69,00,74,00,6f,00,72,00,46,00,69,00,6c,00,65,00, 73,00,3e,00,44,00,6f,00,54,00,5d,00,6a,00,49,00,7b,00,6a,00,66,00,28,00,3d, 00,31,00,26,00,4c,00,5b,00,2d,00,38,00,31,00,2d,00,5d,00,20,00,2f,00,70,00, 74,00,20,00,22,00,25,00,31,00,22,00,20,00,22,00,25,00,32,00,22,00,20,00,22, 00,25,00,33,00,22,00,20,00,22,00,25,00,34,00,22,00,00,00,00,00