I have an iMac with Snow Leopard. I have been using NI 4.7Pro and Elements 3 for quite a long time. However, I have downloaded a trial version of Elements 9 and it doesn't seem to be compatible with 4.7Pro. I guess I should upgrade NI to 6, but is NI6 compatible with PSE 9? Thank you.
Both 4.7 and 6.x should work in PSE9. You may just need to manually install the plug-in to PSE9 using the instruction supplied with the plug-in ( /Applications/NeatImage/HowToInstallPlugin.txt ).