WordPress produces:

<figure>
    <img src="summer.jpg" alt="Alt text">
    <figcaption>Image caption</figcaption>
</figure>

Then the Adaptive Images plugin transforms this to:

<figure>
    <img adaptive-images-src="summer.jpg" alt="Alt text">
    <figcaption>Image caption</figcaption>
</figure>

Which in the browser on DOM load becomes:

<figure>
    <img adaptive-images-src="summer.jpg?resolution=360,1" alt="Alt text">
    <figcaption>Image caption</figcaption>
</figure>