It is always better to actually attach an image to your posts, because it will remain there (assuming no internal site misfortune happens). However, if you link to an image on your device, it can only be seen here for as long as that image is in the same place. If you move it (to another location in your device, or off of your device) it will no longer be visible here.

So, having downloaded your photo—it is attached here.

Jamey