Upload image size information

[mjumbewu]

Feature Description

Determine the size of an image and upload with the attachment. Works with https://github.com/openplans/shareabouts-api/issues/37

This is going to be in the onInputFileChange method in place-form-view.

Steps to consider

• [ ] Research how to get the image size to send up
• [ ] Add the image size info to the attachment payload
• [ ] Identify templates for displaying attachments
• [ ] Apply image size information to rendered images

This feature is done when ...

• An image that we upload to the API has size information that goes with it
• We get image size information back for uploaded images
• Image containers don't jump to new sizes after image download