Trying to render the following .rst with the attached image triggers an infinite loop. I have verified that this issue exists on master.

.. figure:: ./loop.png
    :width: 80%

    This figure triggers an infinite loop while rendering.

I believe that the issue is caused by some combination of the width attribute and the dimensions of the image file. Removing the attribute or changing the image dimensions will work around the issue.

I have tried to find the root cause, but I am having trouble following the rendering logic.

@brechtm can you suggest any tips for figuring out what is going wrong?