add alternate text for images. EPUB validation fails if not present

Author: Jason Cumiskey

docs/getting-started.md

@@ -9,7 +9,7 @@ TypeScript compiles into JavaScript. JavaScript is what you are actually going t
 * A TypeScript editor (you can use notepad if you want but I use [alm 🌹](http://alm.tools). Also [lots of other IDES support it as well]( https://github.com/Microsoft/TypeScript/wiki/TypeScript-Editor-Support))
 
 
-![](https://raw.githubusercontent.com/alm-tools/alm-tools.github.io/master/screens/main.png)
+![alm editor window](https://raw.githubusercontent.com/alm-tools/alm-tools.github.io/master/screens/main.png)
 
 
 ## TypeScript Version

docs/javascript/recap.md

@@ -2,7 +2,7 @@
 
 There were (and will continue to be) a lot of competitors in *Some syntax* to *JavaScript* compilers. TypeScript is different from them in that *Your JavaScript is TypeScript*. Here's a diagram:
 
-![](https://raw.githubusercontent.com/basarat/typescript-book/master/images/venn.png)
+![JavaScript is TypeScript](https://raw.githubusercontent.com/basarat/typescript-book/master/images/venn.png)
 
 However it does mean that *you need to learn JavaScript* (the good news is *you **only** need to learn JavaScript*). TypeScript is just standardizing all the ways you provide *good documentation* on JavaScript.
 

docs/promise.md

@@ -174,7 +174,7 @@ Admittedly this is not hard to follow once you've done it a few times but noneth
 
 A promise can be either `pending` or `fulfilled` or `rejected`.
 
-![](https://raw.githubusercontent.com/basarat/typescript-book/master/images/promise%20states%20and%20fates.png)
+![promise states and fates](https://raw.githubusercontent.com/basarat/typescript-book/master/images/promise%20states%20and%20fates.png)
 
 Let's look at creating a promise. It's a simple matter of calling `new` on `Promise` (the promise constructor). The promise constructor is passed `resolve` and `reject` functions for settling the promise state:
 

header.html

@@ -3,7 +3,7 @@
       var el = document.querySelector('.search-noresults');
       if(el) {
         var elChild = document.createElement('div');
-        elChild.innerHTML = '<a href="https://paypal.me/basaratali" style="display: block;text-align: center;"> Buy me a beer / coffee 🍻 ☕️ 🌹 <br><br><img src="https://img.shields.io/badge/Donate-PayPal-green.svg"><br><br></a>';
+        elChild.innerHTML = '<a href="https://paypal.me/basaratali" style="display: block;text-align: center;"> Buy me a beer / coffee 🍻 ☕️ 🌹 <br><br><img src="https://img.shields.io/badge/Donate-PayPal-green.svg" alt="donate"><br><br></a>';
         el.insertBefore(elChild, el.firstChild);
         clearInterval(interval);
       }