When you go to edit the page, switch from the Visual view, to the Text view. There’s two small tabs, upper right of the editing area. When in the Text view, you will see the HTML code used to create the table.
Typically a table will look like this ..
<table border="1" style="width:100%">
<tr>
<td><img src="nameof image.jpg" height="100" width="200"></td>
<td><img src="nameof image.jpg" height="100" width="200"></td>
<td><img src="nameof image.jpg" height="100" width="200"></td>
</tr>
<tr>
<td><img src="nameof image.jpg" height="100" width="200"></td>
<td><img src="nameof image.jpg" height="100" width="200"></td>
<td><img src="nameof image.jpg" height="100" width="200"></td>
</tr>
</table>
**Before doing the steps below…copy ALL the HTML code you see, and paste it into a text editor, and save it as a .txt file, on your local computer. That way, if you make a mistake..you can easily copy it back to your WP page.**
With the editor in Text view…
Copy the last <tr> </tr> part, including the <td>’s Each <tr></tr> is a row. If you copy the last row, and then just above the final </table> tag…paste it..you will have inserted a new row with the same images as the row you copied. You should now be able to go into Visual view..and edit the individual images.
An even better “fix”, would be to create a Gallery for the images. Much easier for you to maintain. Here’s a couple of tutorials …
https://www.wpbeginner.com/beginners-guide/how-to-create-an-image-gallery-in-wordpress/