bug#28518: Daemon mode only renders the first image file loaded

[Paul Eggert]

On 10/17/2017 07:42 AM, Eli Zaretskii wrote:
> IME such workarounds should be conditioned on the
> pertinent versions of ImageMagick, otherwise they might get in the way
> further down the road.

Normally I'd do that, and I first wrote code to operate that way. 
However, in this particular case the version-number testing code (which 
must be done at runtime, and cannot be done via simple integer 
comparison) was significantly more complicated and error-prone than 
simply working around the bug everywhere. As the workaround changes 
Emacs to use ImageMagick the way most other programs use ImageMagick, 
it's unlikely to cause problems in the future.