Revert "alt -> title"

This reverts commit 2f112dc184.

3. Coexistence with Legacy IPv4/Translation.md

@@ -42,7 +42,7 @@ Point 3 above may be implemented (in addition to points 1 and 2) by various tech
 [RFC 9313](https://www.rfc-editor.org/info/rfc9313) has a good overview and comparison of these technologies.
 
 The following figure illustrates such a scenario.
-<img src="./vasilenko-IPv4aaS.svg" title="User devices connected to Internet via IPv6 infrastructure" width="auto" height="auto"/>
+<img src="./vasilenko-IPv4aaS.svg" alt="User devices connected to Internet via IPv6 infrastructure" width="auto" height="auto"/>
 
 - 464XLAT is the widely preferred translation technology now because it has a natural synergy with NAT64 (which is highly desirable by itself) and because it is the only solution supported on mobile devices. The centralized NAT64 engine is called PLAT, and is the same \[[RFC 6146](https://www.rfc-editor.org/info/rfc6146)] as for ordinary NAT64. The client side is called CLAT, and is typically a stateless NAT46 translation \[[RFC 7915](https://www.rfc-editor.org/info/rfc7915)]. A good analysis of deployment considerations is in [RFC8683](https://www.rfc-editor.org/info/rfc8683), from which an operator might conclude *not* to implement DNS64, since IPv4 clients can simply use the normal DNS A records and the IPv4 service as if it was native.
 

5. Deployment/Deployment by carriers.md

@@ -3,7 +3,7 @@
 All the organizations providing or using Internet connectivity services have an associated Autonous System Number (ASN).
 [APNIC](https://blog.apnic.net/2022/01/06/bgp-in-2021-the-bgp-table/) provides statistics on the evolution of IPv6 support across the ASNs in the world, as observed in the Internet routing tables.
 
-<img src="./Section5_Table2.jpg" title="Table shows 18% annual IPv6 growth 2018 to 2022">
+<img src="./Section5_Table2.jpg" alt="Table shows 18% annual IPv6 growth 2018 to 2022">
 
 The percentage of IPv6-capable ASNs is growing over the years, which is a good sign.
 On the other hand, the table does not allow to understand the degree of adoption across the different industries, that is whether the ASNs are associated to a carrier, a service provider or an entreprise.

5. Deployment/Status.md

@@ -18,7 +18,7 @@ provides data measuring the number of hits to their content delivery platform.
 We have selected this latter statistic, as it comes from a Regional Internet Registry (RIR)
 to show the number of the Internet IPv6 users compared with the total Internet population (in million, see next table).
 
-<img src="./Section5_Table1.jpg" title="Table shows 25% annual IPv6 growth 2018 to 2022">
+<img src="./Section5_Table1.jpg" alt="Table shows 25% annual IPv6 growth 2018 to 2022">
 
 A third of the Internet population actually employs IPv6.
 It is also interesting to look at the growth curve. The main indicator here is

6. Management and Operations/Multi-prefix operation.md

@@ -9,7 +9,7 @@ Here is an illustrative example. Suppose provider X has obtained the prefix ```2
 (To make the example more legible, we have not used randomized IID values.)
 
 The following diagram shows the example:
-<img src="./multiPrefix.svg" title="Routers and routing clouds as described above">
+<img src="./multiPrefix.svg" alt="Routers and routing clouds as described above">
 If, for some reason, there is more than one subnet router on the subnet, the host can be informed which one to use as suggested in [RFC8028](https://www.rfc-editor.org/info/rfc8028).
 
 In normal circumstances, it isn't hard to configure routing so that traffic from ```2001:db8:abcd:0101::abc1``` exits the site towards ISP X, and traffic from ```2001:db8:b123:0101::def2``` exits towards ISP Y. A suitable source routing rule in the subnet router will do it. But what happens if the link to ISP X goes down? Presumably the reason for having two ISP connections is precisely for backup.

99. Chapter Template/Markdown Usage.md

@@ -61,11 +61,11 @@ flowchart LR
 Other types of diagrams could be included using SVG generated by a separate drawing tool such as *dia*, with the SVG file also stored here on GitHub, e.g.:
 
 ~~~
-<img src="./diag.svg" title="Disk feeding tape">
+<img src="./diag.svg" alt="Disk feeding tape">
 ~~~
-<img src="./diag.svg" title="Disk feeding tape">
+<img src="./diag.svg" alt="Disk feeding tape">
 
-Please add title text to help people with visual difficulties.
+Please add alternate text to help people with visual difficulties.
 
 Existing diagrams in PNG or JPG format can be inserted in the same way, although SVG has the advantage of being a text format "under the covers".
 

Contents.md

@@ -1,5 +1,5 @@
 # book6: A Collaborative IPv6 Book.
-<img src="./book6logo.png" title="book6 logo" width="200px" height="auto"/>
+<img src="./book6logo.png" alt="book6 logo" width="200px" height="auto"/>
 This is the current list of contents. It will change as the book evolves.
 There is also an [index](https://github.com/becarpenter/book6/blob/main/Index.md).
 

Index.md

@@ -1,5 +1,5 @@
 # book6 Main Index
-<img src="./book6logo.png" title="book6 logo" width="200px" height="auto"/>
+<img src="./book6logo.png" alt="book6 logo" width="200px" height="auto"/>
 
 Generated at 2023-01-02 10:48:17 UTC+1300
 

README.md

@@ -1,4 +1,4 @@
-<img src="./book6logo.png" title="book6 logo" width="200px" height="auto">
+<img src="./book6logo.png" alt="book6 logo" width="200px" height="auto">
 
 A collaborative IPv6 book.
 

utilities/indexBook.py

@@ -7,7 +7,7 @@
 # Version: 2022-12-27 - cosmetic improvements
 # Version: 2022-12-28 - allow keywords starting with digit
 # Version: 2022-12-30 - include timestamp
-# Version: 2023-01-02 - added title text to logo
+# Version: 2023-01-02 - added alt text to logo
 
 
 ########################################################
@@ -264,7 +264,7 @@ for i in range(len(index)):
         index[i] = index[i].replace(head, '['+blob)
 
 index.insert(0,'# book6 Main Index\n')
-index.insert(1,'<img src="./book6logo.png" title="book6 logo" width="200px" height="auto"/>\n\n')
+index.insert(1,'<img src="./book6logo.png" alt="book6 logo" width="200px" height="auto"/>\n\n')
 index.insert(2,"Generated at "+timestamp+"\n\n")
 index.insert(3,"This index was created automatically, so it's dumb. ")
 index.insert(4,"It is not case-sensitive. ")