Post-formats "image" question

Hi,

I’m currently working on a fully responsive Bootstrap based theme, and I implemented all post formats from Twentyforteen.

Codex defines post format image as:

A single image. The first <img /> tag in the post could be considered the image. Alternatively, if the post consists only of a URL, that will be the image URL and the title of the post (post_title) will be the title attribute for the image.

Currently Twentyforteen just uses “the_content()”, which outputs the hard coded image tag. In sidebar or index view this leads to heavy browser scaling, which should be avoided. If the editor entered additional text above or under the image, this text is rendered as well. If he or she enters multiple images, all of them are rendered. Is this expected behavour? What is the “feature” behind post-format “image”? Shouldn’t it just be a singular image with or without a caption?

If so, would it be ok to use the “post_thumbnail” feature for this single image? The post_thumbnail gives you full control over the image to deliver in sidebar, index- or single view, avoiding any browser scaling. Besides that, a post_thumbnail is singular. A post would only consist of a title and a post_thumbnail, with or without caption. Any content enterred would be ignored. This would not exactly match the Codex definition of post format “image”, but it would be closer to it than Twentyforteen is today.

What is the use of post-formats if they all behave like standard posts?

Thanks for any thoughts,

Thomas