docs: localize FAQ images

docs/FAQ.md

@@ -182,7 +182,7 @@ You can [modify a tool's build configuration](How-to-Build-Software-Outside-Home
 
 Chances are that certain apps will give you a popup message like this:
 
-<img src="https://i.imgur.com/CnEEATG.png" width="532" alt="Gatekeeper message">
+<img src="assets/img/docs/gatekeeper-unidentified-message.png" width="532" alt="Gatekeeper unidentified developer message">
 
 This is a [security feature from Apple](https://support.apple.com/en-us/HT202491). The single most important thing to know is that **you can allow individual apps to be exempt from this feature.** This allows the app to run while the rest of the system remains under protection.
 
@@ -190,11 +190,11 @@ This is a [security feature from Apple](https://support.apple.com/en-us/HT202491
 
 If you're sure you want to trust the app, you can disable protection for it by right-clicking its icon and choosing *Open*:
 
-<img src="https://i.imgur.com/69xc2WK.png" width="312" alt="Right-click the app and choose Open">
+<img src="assets/img/docs/right-click-choose-open.png" width="312" style="margin-left:60px" alt="Right-click the app and choose Open">
 
 In the resulting dialog, click the *Open* button to have macOS permanently allow the app to run on this Mac. **Don’t do this unless you’re sure you trust the app.**
 
-<img src="https://i.imgur.com/xppa4Qv.png" width="532" alt="Gatekeeper message">
+<img src="assets/img/docs/gatekeeper-unidentified-open.png" width="532" alt="Gatekeeper unidentified developer open prompt">
 
 Alternatively, you may provide the [`--no-quarantine` flag](https://github.com/Homebrew/homebrew-cask/blob/HEAD/USAGE.md#options) at install time to not add this feature to a specific app.
 
@@ -204,7 +204,7 @@ After running `brew upgrade`, you may notice some casks you think should be upgr
 
 As you’re likely aware, a lot of macOS software can upgrade itself:
 
-<img src="https://upload.wikimedia.org/wikipedia/commons/c/c0/Sparkle_Test_App_Software_Update.png" width="532" alt="Sparkle update window">
+<img src="assets/img/docs/sparkle-test-app-software-update.png" width="600" alt="Sparkle update window">
 
 That could cause conflicts when used in tandem with Homebrew Cask’s `upgrade` mechanism.