Image magic is overrun? Not all images are rendered.

When opening a rather large gallery some images are cut in halv. It looks like the stream is broken. I assume it has something to do with timeout or image magic conversion limit. 

<img width="1189" alt="screen shot 2015-12-01 at 13 13 24" src="https://cloud.githubusercontent.com/assets/497958/11500450/6c9e762c-982d-11e5-8651-624e3e637572.png">
