Revert "Revert "Add RMagick back""

This reverts commit dc238e237b1891688fe69b85edca45ccd6ee6b76.
Revert "Revert "Rudimentary image support""

This reverts commit b6aef080810800b6b3478447e075ae39e542ffdf.
Revert "Revert "typo""

This reverts commit 252a4fe6ed823b2588a644b287e33f07358f43e9.
Revert "Revert "Use the actual image sizes.""

This reverts commit 38640ee4e60442af5c28d90e5964a5048853928b.
rmagick -> RMagick