Our app was already deployed and working on Heroku with MiniMagick. There were a few features of Image Processing that were appealing, performance and autorotation, and it appeared to be a straightforward swap.
Locally, we had run brew install vips on our MacBooks to get it running. That was early in the process and a detail long forgotten. When I deployed to Heroku @juliancheal pointed out that the staging environment was failing with an ActiveSupport::MessageVerifier::InvalidSignature error.
We were able to quickly identify the missing libvips dependency.
Figuring out how to install libvips to support rubyvips to support Image Processing was not trivial and therefore this guidepost exists.