Just to show you:
In Opera 12, you can goto "Menu -> Mail and Chat accounts -> Import Mail -> Import Generic Mbox" and choose to import:
remoteimagecerttest.mbs:
From From: from@example.com To: to@example.com Subject: Remote Image Cert Test Content-type: text/html; charset="utf-8"> Content-Transfer-Encoding: 8bit <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Remote Image Cert Test</title> </head> <body> <p><img src="https://cdn.arstechnica.net/wp-content/uploads/2025/05/rx-9060-xt-slide-1440x806.jpg"></p> </body> </html>into a new account. Then, when you load the message and choose to load images for it, you'll be asked to approve the cert. You can then switch to the "Security" tab and approve it.
Then, hit alt + p, switch to "Advanced -> Security", click "Manage Certificates" and switch to the "Approved" tab to see that cert.
The standalone Opera Mail works the same way. It just doesn't have that "Manage Certificates" dialog.
With that said, not sure what type (if any) cert you can import to automatically approve all certs from all domains whether there are cert errors or not.
