Image Disappear When Re-Update the Post

[jokusuma]

Hi Bobby, thanks so much for taking time to create awesome WordPress tutorials.
I followed your plugin series videos and image uploader series, they are helping me to understand WordPress better. Again, thank you.

Moreover, on the image uploader series, I found out that the image thumbnail disappear when I re-update the custom post type. The source (url) of the image become "undefined" although the data still on the database (wp_postmeta).

I tried several options but it didn't work. Can you please help?

Best Wishes
Jo