Photo Trouble

I seem to be having trouble when uploading photos to my site…they come through okay at first and then later all I see are X where the photos should be.

I cant seem to figure this out. It seems to happen ALL the time when I copy a listing and only sometimes when I enter a NEW listing..

https://www.moonlightstamper.com/products-page/wedding-invitations/coral-seashell-wedding-invitation-with-ribbon-belly-band

Thanks very much!
Wendy