How to debug slow Chrome on MacBook Air?
I'd start by creating a new "User" in Chrome.

Chrome &gt; Preferences: New User

This will give you a fresh start on preferences and extensions.

If the new user has no issue then you likely have a bad extension or preference.

Chrome and Safari are both memory pigs these days (in exchange for which they are wicked fast when they have enough memory).  How much RAM does your Air have?

When you look at the Chrome console when images fail to load is there anything interesting there?  Chrome &gt; View &gt; Developer &gt; JavaScript Console