image will be resized to fit into a 200x200 box, rather than being squashed into a square or whatever shape is specified.

e.g.

original:
![image](https://f.cloud.github.com/assets/43438/1445082/4b094022-4218-11e3-8428-48dca31f7647.png)

aspect ratio ignored:
![image](https://f.cloud.github.com/assets/43438/1445083/523ee96e-4218-11e3-8266-9002b86cf407.png)

aspect ratio maintained:
![image](https://f.cloud.github.com/assets/43438/1445085/5a383d46-4218-11e3-8511-a944ccd96d86.png)

I actually can't think of many cases where you'd want to resize an image without maintaining aspect ratio.

I'll update this text later tonight to explain better