Render stock image for broken recipe pictures

[coren-frankel]

If an image doesn't render, provide a default "stock" image. To do this, we may need to get clever. Perhaps use a background image to load stock image behind the original image.

[coren-frankel]

Let's see if we can solve this with some raw HTML, if not more robust components based on the picture tag.

This might be easier than I had thought.