Just so that people know - copying pictures between fields leads to significant quality loss.
I am not talking about copying the whole field into another field. But rather right-click copy image or right-click copy URL and then open the other field attachment viewer and pasting the image or the URL (same thing).
This leads to quality loss. Original picture has higher quality and resolution. The loss happens in particular with more loss-less picture formats like PNG.
I don’t know if it is still possible to extract the original image from Airtable throuth background download (CSV export), haven’t tried it yet.
The only way to preserve the quality of the image is to download the image and again upload in the other field, or the copy the whole field and past all attachments into the other field.