Thanks Eric, Colin. 

Please see my further questions below. 

>>>>> Eric S Fraga <esflists@gmail.com> writes: 

    > Your example works fine for me but I am using a slightly old
    > version of org so maybe something has changed?

    > -- Eric S Fraga via Emacs 27.0.50, Org release_9.1.14-1035-gfeb442

I see that you are running Emacs master. Can you also report the git hash used to build it? Also, what is your imagemagick version?

On Wed, Jan 9, 2019, 3:18 AM Colin Baxter <m43cap@yandex.com wrote:

Works fine for me too and I'm using Org mode version 9.2
(release_9.2-152-gc006a6).

Great! So any regression in Org mode 9.2 is ruled out :)

I need to see what's different in my environment: Emacs version, imagemagick version. 

Later today, I'll find out my imagemagick version, and also try running my example on Emacs 26.1. 

Thanks all!