Ok, I'm going to try figuring this out from what you said.
Look at your HTML code. Specifically, look for an img element, which should look something like this:
Note: The link is going to be completely different than what I used above.
Alright, so once you've found that, you're going to include the class that it is asking for(that is, smaller-image).
To add a class to an image, you'd do something like this:
<img src="www.someLinkHere.com" class="add-class-here">
I noticed you mentioned two images, so add the appropriate class names to each image, if they're not already there.
Now, the images are out of the way, and what it is asking you to do to them is to style the images with the following:
The border's width should be 10px
The border should be solid.
The border's color should be green.
Perhaps try to combine your three rules.
So instead of this:
try to condense it into a single line. I could be wrong, but I think that's what the challenge is asking for.