Changing attributes e.g `aspect ratio` breaks images in amp-mode.

Steps to reproduce:

1. Create an AMP page inside the editor.
2. Add an image with desired ratio and other attributes.
3. Save page.
4. Edit image attributes such as aspect ratio.

No images will be visible and the following error shows up in the console:

Uncaught Error: The last option must not have a media condition​​​
    at Za.f.assert (log.js:429)
    at D (log.js:995)
    at new mi (size-list.js:167)
    at li (size-list.js:136)
    at HTMLElement.Di.b.applySizesAndMediaQuery (custom-element.js:680)
    at ci.f.applySizesAndMediaQuery (resource.js:374)
    at h (resources-impl.js:1173)
    at yj.setState (finite-state-machine.js:72)
    at Cj.f.doPass (resources-impl.js:743)
    at ji.Ug (resources-impl.js:134)

[homanp]

@mrkoreye so I figured out that this only happens in amp-mode when you put an image inside a box. Not otherwise.

[mrkoreye]

Thanks, that should help! I will let you know if I need anything else to investigate.