docs: use local copies of images rather than external URLs (vuejs#914)

src/cookbook/editable-svg-icons.md

@@ -18,7 +18,7 @@ First, we'll create a folder for all of the icons, and name them in a standardiz
 
 Here's an example repo to get you going, where you can see the entire setup: [https://github.com/sdras/vue-sample-svg-icons/](https://github.com/sdras/vue-sample-svg-icons/)
 
-![Documentation site](https://s3-us-west-2.amazonaws.com/s.cdpn.io/28963/screendocs.jpg 'Docs demo')
+![Documentation site](/images/editable-svg-icons.jpg 'Docs demo')
 
 We'll create a base icon (`IconBase.vue`) component that uses a slot.
 
@@ -88,7 +88,7 @@ Now, if we'd like to make many sizes for the icon, we can do so very easily:
 </p>
 ```
 
-<img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/28963/Screen%20Shot%202018-01-01%20at%204.51.40%20PM.png" width="450" />
+<img src="/images/editable-svg-icons-sizes.png" width="450" />
 
 ## Animatable Icons
 

src/guide/composition-api-introduction.md

@@ -57,7 +57,7 @@ This component has several responsibilities:
 
 Organizing logics with component's options (`data`, `computed`, `methods`, `watch`) works in most cases. However, when our components get bigger, the list of **logical concerns** also grows. This can lead to components that are hard to read and understand, especially for people who didn't write them in the first place.
 
-![Vue Option API: Code grouped by option type](https://user-images.githubusercontent.com/499550/62783021-7ce24400-ba89-11e9-9dd3-36f4f6b1fae2.png)
+![Vue Options API: Code grouped by option type](/images/options-api.png)
 
 Example presenting a large component where its **logical concerns** are grouped by colors.
 

src/guide/contributing/writing-guide.md

@@ -57,7 +57,7 @@ Writing documentation is an exercise in empathy. We're not describing an objecti
 
 - **Avoid abbreviations** in writing and code examples (e.g. `attribute` is better than `attr`, `message` is better than `msg`), unless you are specifically referencing an abbreviation in an API (e.g. `$attrs`). Abbreviation symbols included on standard keyboards (e.g. `@`, `#`, `&`) are OK.
 - **When referencing a directly following example, use a colon (`:`) to end a sentence**, rather than a period (`.`).
-- **Use the Oxford comma** (e.g. "a, b, and c" instead of "a, b and c"). ![Why the Oxford comma is important](https://raw.githubusercontent.com/vuejs/vuejs.org/master/src/images/oxford-comma.jpg)
+- **Use the Oxford comma** (e.g. "a, b, and c" instead of "a, b and c"). ![Why the Oxford comma is important](/images/oxford-comma.jpg)
   - Source: [The Serial (Oxford) Comma: When and Why To Use It](https://www.inkonhand.com/2015/10/the-serial-oxford-comma-when-and-why-to-use-it/)
 - **When referencing the name of a project, use the name that project refers to itself as.** For example, "webpack" and "npm" should both use lowercase as that's how their documentation refers to them.
 - **Use Title Case for headings** - at least for now, since it's what we use through the rest of the docs. There's research suggesting that sentence case (only first word of the heading starts with a capital) is actually superior for legibility and also reduces the cognitive overhead for documentation writers, since they don't have to try to remember whether to capitalize words like "and", "with", and "about".