The thing about every single piece of photo edit software is that it doesn’t fit any computer. Instead, it has some clear hardware specifications that need to be fulfilled in order for it to run.
Usually, the hardware resources and image retouch program needs are a function of how professional that certain program is. For example, the photo edit software that I use, as a professional, is more demanding than those used by people who like to spend their spare time playing with their photos.
This dependence is absolutely natural, if you come to think about it: I am willing to spend money on good, performing editing software, because by working with top class tools I can achieve the most amazing things in my image retouch activity.
This isn’t to say that free downloads or less demanding editing programs are no good. Things are always contextual, and the resolution (effective/ ineffective; useful/ useless; appropriate/ inappropriate) is always determined by a bunch of external factors. What I’m trying to say is that regular photo editing software might be all you need sometimes, but, let’s face it, great tools handled by professionals always make a huge difference.
The point here is to think twice before spending your money on photo edit software. Instead, you can turn to real pros whenever you need to have your photos readjusted or modified, and, as long as they know exactly what you want, they can provide the best results.