Update tutorial-discovering.asciidoc (#76976) (#78630)

* Update tutorial-discovering.asciidoc

Adds alt text to images in doc.

* Update docs/getting-started/tutorial-discovering.asciidoc

* Update docs/getting-started/tutorial-discovering.asciidoc

Co-authored-by: Kaarina Tungseth <kaarina.tungseth@elastic.co>
# Conflicts:
#	docs/getting-started/tutorial-discovering.asciidoc

Co-authored-by: ncheckin <68351161+ncheckin@users.noreply.github.com>

Author: KOTungseth

docs/getting-started/tutorial-discovering.asciidoc

@@ -22,13 +22,15 @@ The search returns all account numbers between zero and 99 with balances in
 excess of 47,500. Results appear for account numbers 8, 32, 78, 85, and 97.
 +
 [role="screenshot"]
-image::images/tutorial-discover-2.png[]
-
+image::images/tutorial-discover-2.png[Image showing the search results for account numbers between zero and 99, with balances in excess of 47,500]
++
 . Hover over the list of *Available fields*, then
 click *Add* next to each field you want include in the table.
 +
 For example, when you add the `account_number` field, the display changes to a list of five
 account numbers.
 +
 [role="screenshot"]
-image::images/tutorial-discover-3.png[]
+image::images/tutorial-discover-3.png[Image showing a dropdown with five account numbers, which match the previous query for account balance]
+
+Now that you know what your documents contain, it's time to gain insight into your data with visualizations.