feat(user_manual): update screenshots and feature description (Talk 18.0+)

Signed-off-by: Maksim Sukharev <antreesy.web@gmail.com>

user_manual/talk/join_a_call_or_chat_as_guest.rst

@@ -9,11 +9,11 @@ You can find out more about Nextcloud Talk `on our website <https://nextcloud.co
 Joining a chat
 --------------
 
-If you received a link to a chat conversation, you can open this in your browser to join the chat.
+If you received a link to a chat conversation, you can open it in your browser to join the chat. Here, you will be prompted to enter your name before joining.
 
 .. image:: images/guest-view.png
 
-You can change your name by clicking the ``Edit`` button, located top-right.
+You can also change your name later by clicking the ``Edit`` button, located top-right.
 
 .. image:: images/change-name.png
 
@@ -30,7 +30,8 @@ You can start a call any time with the ``Start call`` button. Other participants
 
 Before actually joining the call you will see a device check, where you can pick the right camera and microphone, enable background blur or even join with any devices.
 
-.. image:: images/device-check.png
+.. image:: images/device-settings-before-call.png
+    :width: 300px
 
 During a call, you can find the Camera and Microphone settings in the ``...`` menu in the top bar.
 

user_manual/talk/talk_basics.rst

@@ -77,7 +77,7 @@ Second, you can select a file from your Nextcloud Files or a file manager by cho
 .. image:: images/share-files-in-chat-selection.png
     :width: 450px
 
-You can add more files until you are done and decide to share the files.
+You can add more files until you are done and decide to share the files. You can also add a text caption to your shared files, providing a brief description or context.
 
 .. image:: images/talk-upload-files.png
    :width: 500px
@@ -237,7 +237,9 @@ Starting a screen share
 -----------------------
 
 You can click the monitor icon on your video stream to share your screen. Depending on your browser, you will get the option to share a monitor, an application window or a single browser tab.
+If video from your camera is also available, other participants will see it in a small presenter view next to the screen share.
 
+.. image:: images/share-screen-with-camera.png
 
 Changing view in a call
 -----------------------