This error occurs when you have a Hyperlink or Picture column and you specify the URL format as Picture instead of Hyperlink. When you try to update the column using PowerApps, you will encounter the error “The specified column is generated by the server and can’t be specified”.

If the link points to an image, and you want to have a preview of the image in the list view, the solution is to make the format as Hyperlink, and use column formatting to show the image. This will not only allow you to save the column, but have a preview of the image as well.

You can use the following JSON for the column formatting.

   "$schema": "",
   "elmType": "div",
   "children": [
       "elmType": "img",
       "attributes": {
         "src": "@currentField",
         "title": "=if(@currentField == '', 'No picture available', @currentField)"
       "style": {
         "position": "relative",
         "top": "50%",
         "left": "50%",
         "width": "100px",
         "height": "auto",
         "margin-left": "-50%",
         "margin-top": "0%"