Please update the editor to have the ability to add images by pasting from the clipboard, in the details tab of Instant Apps. Currently images added in this way do not show in the final product.
Only the text will appear when using the app, the image(s) do not show in the Sidebar Instant App
The functionality could be similar to webapp classic About widget
Text and images can quickly be added and updated by simply pasting an image into the editor.
Both Text and images show in webapp classic
Another example is it could work the same way the Esri community comment section work. With Text and Images being dropped into the same editor