My wife's Win10 (x64) notebook has 8GB RAM (which cannot be expanded) & a 500GB SSD. She does quite a bit of photo-editing (mostly on Picasa), so I was wondering what would be the optimum setting for her pagefile; i.e., leave it as is (Windows managed) or set a custom (fixed) size?
Fwiw, I recently replaced my HDD with an SSD, installing Win10 x64 on the SSD. As with your wife's notebook I have 8GB RAM and I also use Picasa to edit my photos, although (sadly) it is no longer being developed. Anyhow (re your question), I have not changed the default pagefile settings and I couldn't be more pleased with how fast Picasa (and everything else) is running!
I have it disabled for years, even when I had only 512 MB of RAM. Never had any problems on my XP, huge GUI boost on HDDs.