I have a file with just the following 4 lines:
<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
<span style="outline:1px dotted green">
<i class="material-icons">imagesmode</i>
</span>
The first line is just copied from Material Icons Guide. The rest is how I usually inserts an icon.
The result looks like this:
I expected just the first icon. (And with a little dot.) Am I doing something wrong?
EDIT: It seems to be a documentation problem in Material Icons Guide. Anyone knows where to report this specific problem?

Simply replace your icon to
You can find the code at Google Fonts Icon by clicking the icon you need, and there will be a side bar popup. Scroll down to the "Inserting Icon" section and copy the code. In your case, you can just replace the icon name.