doc/testnet/atomic-swap: add screenshots and minor edits

doc/src/testnet/atomic-swap.md

@@ -1,27 +1,31 @@
 # Atomic Swaps
 
-In order to do an atomic swap with someone, you will first have to come
-to a consensus on what tokens you wish to swap. For example purposes,
-let's say you want to swap `40` `WCKD` (which is the balance you
-should have left over after doing the payment from the previous page)
-for your counterparty's `20` `MLDY`. For this tutorial the counterparty
-is yourself.
+In order to do an atomic swap with someone, you will first have to agree
+on what tokens you wish to swap. For example purposes, let's say you want
+to swap `40` `WCKD` (which is the balance you should have left over after
+doing the payment from the previous page) for your counterparty's `17.31`
+`MLDY`. For this tutorial the counterparty is yourself.
 
 To protect your anonymity from the counterparty, the swap can only send
-entire coins. To create a smaller coin denomination, send yourself
-the amount you want to swap. Then check you have a spendable coin to
-swap with:
+entire coins. To create a smaller coin denomination, send yourself the
+amount you want to swap. Then check you have a spendable coin to swap
+with. Note that the coin overview might look very different depending
+on your activity:
 
 ```
 $ ./drk wallet --coins
 ```
 
+![coins](img/spent-coins.png)
+
 You'll have to initiate the swap and build your half of the swap tx:
 
 ```
-$ ./drk otc init -v 40.0:20.0 -t WCKD:MLDY > half_swap
+$ ./drk otc init -v 40.0:17.31 -t WCKD:MLDY > half_swap
 ```
 
+![halfswap](img/halfswap.png)
+
 Then you can send this `half_swap` file to your counterparty and they
 can create the other half by running:
 
@@ -29,6 +33,8 @@ can create the other half by running:
 $ ./drk otc join < half_swap > full_swap
 ```
 
+![fullswap](img/fullswap.png)
+
 They will sign the full_swap file and send it back to you. Finally,
 to make the swap transaction valid, you need to sign it as well
 
@@ -36,6 +42,8 @@ to make the swap transaction valid, you need to sign it as well
 $ ./drk otc sign < full_swap > signed_swap
 ```
 
+![signedswap](img/signedswap.png)
+
 Now that the swap is signed, one of the parties (or a third one)
 must attach the corresponding fee:
 
@@ -43,6 +51,8 @@ must attach the corresponding fee:
 $ ./drk attach-fee < signed_swap > full_swap_with_fee
 ```
 
+![signedswapwithfee](img/signedswapwithfee.png)
+
 Since a new call has been added to the transaction, both parties
 must re-sign the full_swap_with_fee file, one by one.
 
@@ -52,18 +62,24 @@ Party A:
 $ ./drk otc sign < full_swap_with_fee > signed_full_swap_with_fee
 ```
 
+![signedswapwithfee2](img/signedswapwithfee2.png)
+
 Party B:
 
 ```
 $ ./drk otc sign < signed_full_swap_with_fee > swap_tx
 ```
 
+![swaptx](img/swap-tx.png)
+
 Now the complete swap transaction can be broadcasted:
 
 ```
 $ ./drk broadcast < swap_tx
 ```
 
+![broadcast](img/broadcastswap.png)
+
 On success, you should see a transaction ID. This transaction will now
 also be in the mempool, so you should wait again until it's confirmed.
 
@@ -75,6 +91,26 @@ After a while you should see the change in balances in your wallet:
 $ ./drk wallet --balance
 ```
 
-If you see your counterparty's tokens, that means the swap was
-successful.  In case you still see your old tokens, that could mean
-that the swap transaction has not yet been confirmed.
+![balances](img/all-balances.png)
+
+Since in this example we did an atomic swap with ourself, the balances are
+unchanged. We can confirm it actually happened successfully by checking
+our coins:
+
+```
+$ ./drk wallet --coins
+```
+
+![coins](img/swapcoins.png)
+
+Here you can see there are two entries for the tokens we used in the
+swap: 17.31 MLDY and 40.00 WCKD. The first entry shows the `Spent` flag
+as `true` and the second entry shows the `Spent` flag as `false`. This
+means the transaction was successful. Since we are swapping with ourself,
+we successfully spent the coins in the first half of the transaction,
+and re-minted to ourselves them in the second half of the transaction.
+
+If you're testing atomic swaps with a counterparty and you can see
+their tokens, that means the swap was successful.  In case you still
+see your old tokens, that could mean that the swap transaction has not
+yet been confirmed.