Let’s break it down:
All html elements can have attributes.
These attributes look like key=value pairs.
So for example, in the <img> element we can set the source of the image with the src attribute: src='http://path.to.image.com'
A really important attribute is class. On it’s own, class does nothing, but when you have a style rule that depends on that class, like .smaller-image (note, the . means class in a css stylesheet), it can change the style of that element.
Elements can have many attributes so it’s not uncommon to see something like this:
<img class='special-style-rule' src='/image.png' alt='a picture' />'
See if you can piece all that together to pass your challenge.