Hello,
Could you please once try deactivating the third party Plugins on your Site and then check back if the original Image code is showing in the Inspect or not.
If it resolves the concern, then reactivate them one by one to know which Plugin is generating that Image code originally.
If somehow issue still persists, then please take complete Backup of your Site first, then provide us the permission to completely debug your Site which includes deactivating all the third party Plugins and removal of on-Site Customization changes too, so that we can thoroughly check this issue on your Site and assist you accordingly.
Best Regards