Move images from a image field to another field
Welcome to SO, MineDoodler!
A little bit ago I found the same problem, so I developed this piece of code. (Note that I started a little bit ago with developing, it is possible to achieve this easier).
Read the comments to understand the code.

use \Drupal\node\Entity\Node;
use \Drupal\paragraphs\Entity\Paragraph;
use \Drupal\file\Entity\File;


function migrateImages() {
  // Get all products
  $query = \Drupal::entityQuery('node');
  $query-&gt;condition('status', 1);
  $query-&gt;condition('type', 'productos');
  $nids = $query-&gt;execute();

  $allNids = [];

  // In my case, i had a keyed array (First element was [213] =&gt; &quot;157&quot;) so I turned into ([0] =&gt; &quot;157&quot;)
  foreach ($nids as $nid) {
    $allNids[] = $nid;
  }

  // Go through every node
  for ($i = 0; $i &lt; count($nids); $i++) {
    $nodeID = $allNids[$i];

    // Load node.
    $node = Node::load($nodeID);

    // Get current paragraphs (if already has any).
    $current = $node-&gt;get('field_prod_media')-&gt;getValue();

    // Go through every image this node has.
    foreach ($node-&gt;field_prod_img as $item) {
      // Create new paragraph
      $paragraph = Paragraph::create(['type' =&gt; 'YOUR_PARAGRAPH_TYPE']);

      // Load image
      $file = File::load($item-&gt;target_id);

      // Save image
      $paragraph-&gt;set('IMAGE_FIELD_IN_PARAGRAPH', $file);

      // Force the new &quot;alt&quot;. I've done this because it wasn't saving the alt.
      $paragraph-&gt;field_img-&gt;alt = $item-&gt;alt;
      
      // Check if it's new and save it.
      $paragraph-&gt;isNew();
      $paragraph-&gt;save();
      
      // Add to the current paragraphs the new one.
      $current[] = array(
        'target_id' =&gt; $paragraph-&gt;id(),
        'target_revision_id' =&gt; $paragraph-&gt;getRevisionId(),
      );
    }
    
    // Set again all paragraphs, with the new ones.
    $node-&gt;set('field_prod_media', $current);
    $node-&gt;save();
    dpm(&quot;node &quot;.$node-&gt;label().&quot; has been saved!&quot;);
  }
}

Took the idea from #7 in this post and developed by my knowledge.
I forgot to mention that this code was executed in the Devel PHP, in the Devel module.