Incompatibility with GoogleCharts BarFormat

![69237-1222013112341pm](https://f.cloud.github.com/assets/633012/87986/18126c3c-64da-11e2-8b70-c7a55b96ff30.png)
With image height auto, we see some images being unnecessarily warped. You can see this problem if you set up a GoogleChart's BarFormat (https://developers.google.com/chart/interactive/docs/reference#barformatter)

Forcing children images to not be re-scaled past their parents imposes an unnecessary restriction on the developer.