Thanks for the advice, but I've wget and curl installed through Mac ports.

$ which crul    => /usr/texbin/curl
$ which wget  => /usr/texbin/wget

And the value of my exec-path is:
("/usr/bin" "/bin" "/usr/sbin" "/sbin"
"/Applications/Documents/Emacs.app/Contents/MacOS/libexec"
"/Applications/Documents/Emacs.app/Contents/MacOS/bin"
"/Applications/Mathematics/MATLAB_R2014a.app/bin"
"/Applications/Documents/Emacs.app/Contents/MacOS/bin" "*/usr/texbin*"
"/opt/local/bin" "/usr/local/bin")

which has included /usr/texbin

Any thoughts?  Thanks.

On Tue, Jan 13, 2015 at 3:58 AM, Rainer M Krug <Rainer@krugs.de> wrote:

> "briangpowell ." <briangpowellms@gmail.com> writes:
>
> > * https://github.com/abo-abo/org-download/blob/master/org-download.el
> has:
> >
> > ...
> > (defcustom org-download-backend t
> >   "Method to use for downloading."
> >   :type '(choice
> >           (const :tag "wget" "wget \"%s\" -O \"%s\"")
> >           (const :tag "curl" "curl \"%s\" -o \"%s\"")
> >           (const :tag "url-retrieve" t))
> >   :group 'org-download)
> > ...
> >
> > ** My guess: You don't have "wget" and/or "curl" on your Mac?
>
> either that, or they are not in the path used in emacs (are they
> installed via e.. homebrew?).
>
> Depending on how you set the paths, the emacs process might have
> different paths.
>
> Cheers,
>
> Rainer
>
> >
> >
> > On Tue, Jan 13, 2015 at 2:49 AM, Chao Lu <loochao.list@gmail.com> wrote:
> >
> >> Dear all,
> >>
> >> Does anyone get org-download.el to work under Mac OSX? I'm struggling to
> >> get it work, but it seems to help a lot, empowering org to handle
> images a
> >> lot easier.
> >>
> >> I believe I've installed org-download.el correctly, but when I'm
> dragging
> >> and drop the image into an org buffer, all I get is the link address
> >> inserted into the buffer, no downloading events trigger.
> >>
> >> I double checked a few things before coming here:
> >> - My system has both curl and download.
> >> - I've set the download image dir to ~/Downloads/Foo
> >> - The value of dnd-protocol-alist contains
> >> ("^\\(https?\\|ftp\\|file\\|nfs\\)://" . org-download-dnd)
> >>
> >> The emacs I'm using is "GNU Emacs 24.3.1 (x86_64-apple-darwin, NS
> >> apple-appkit-1038.36) of 2013-03-13 on bob.porkrind.org"
> >>
> >> Is there any thought what I should check?
> >>
> >> Best,
> >>
> >> Chao
> >>
>
> --
> Rainer M. Krug
> email: Rainer<at>krugs<dot>de
> PGP: 0x0F52F982
>