Use QFileAsset control for model images

```
Describe the feature being requested:
The model image upload process should be updated to use QFileAsset control 
instead of the current method. See company logo in the Admin module for an 
example.

Please use labels and text to provide additional information.

```

Original issue reported on code.google.com by `jsincl...@tracmor.com` on 3 Oct 2011 at 8:12
