support absolute path to load image?

[youkaichao]

In a markdown cell, ![title](img/picture.png) can only display image with a relative path. I searched stackoverflow and find out it seems we can't use an absolute path here.

any ideas to add support for absolute path?

[takluyver]

The paths in markdown are HTTP paths, so they can only access files under the server root.

You can load a file by absolute path in the kernel, and display it as output: http://nbviewer.jupyter.org/github/ipython/ipython/blob/6.x/examples/IPython%20Kernel/Rich%20Output.ipynb#Images