I see people always struggling with include/exclude notation inside use case diagrams. I think these diagrams could explain it better.

Now, lets look at the extended diagram. Notice how connections have changed. The example shows uploading photo and video use case with optional use case of applying filter.

Remember:

• If A includes B: then B must be done inside A.
• If B extends A: then B can be done inside A (A can use B, but not always)

So this is the difference guys. No more content for this post :D