convert file.{png,jpg}
is same as
    convert file.png file.jpg
And, 
    convert *.{png,jpg}
is same as
    convert *.png *.jpg


On Fri, Jun 1, 2018 at 12:32 PM, Stewart C. Russell via talk
<talk@gtalug.org> wrote:
On 2018-05-31 03:00 PM, Stewart Russell wrote:
>
>   convert file.{png,jpg}
>
> and bash will do the magic. What I don't know is if that will accept a
> glob. 

narrator voice: it didn't accept a glob.

(that is,

    convert *.{png,jpg}

does *something*, but neither what you'd expect nor want)