Toast notification (upper right hand notification) should respond to changes the user is making. 

Here are some sample cases I see based on the actions on the page that need their own toast notifications:

• [Blueprint is selected + Build images] = same "image is being built" sequence that we have in Image Builder now
• ["Create blueprint" or "Edit blueprint" + "Save" in the review screen] = "Changes saved to blueprint"
• ["Create blueprint" or "Edit blueprint" + "Save and build" in the review screen] = same "image is being built" sequence that we have in Image Builder now