Optimisation: Avoid expensive Image.write
Optimisation: Avoid expensive Image.write

Large images using one of the profiles which perform
Image.write would spend several seconds (~5 seconds in one
such case) simply writing the image to a file in order
to run the command line convert operation.

Since these profiles are mutually exclusive, and because
up until this point in code no operations are performed
on the image object we simply store the http response
directly into a file instead.

In future if profiles are no longer mutually exclusive,
or if some operations are applied to the image object
directly before using the command line then care will
be needed to ensure the image and/or file are correctly
updated where necessary.

mbst/packs