Just because an idiot software says it is spam then I cannot open it to see what is inside?

What prevents you from opening messages in the Junk folder?

Messages in Junk can be opened just like in any other folder.

Not in my thunderbird. see attached.

There isn't a whole lot to see in your screenshot. A screenshot of the entire message window would be better.

It seems what cannot be seen are the images, but some mails are mostly only that.

Probably there should be an option "show images" then we can insppect the mail and know if thew risk is worth to open the images, otherwise many mails go back to inbox , fooling the spam training that need not.

But the images themselves are part of the problem. The action of downloading one to view can be used to confirm that your email account is active and working and so makes your account more attractive to spammers.

The message you have shown us tells us almost nothing about the sender nor the content. To me that screams out "SPAM!!" and it isn't even worth considering opening it.

Well, You may think it is spam, but I may think not, so I want and it is better that I have the option to see it without sending to inbox, also I have many sending addresses set to go directly to junk because I receive too many mails from them, and do not want to have the inbox cluttered. But often I go see what they have sent, but then I have to send to inbox to see what is in some mails that I want to check. This constant back and forth may not be the bet for training spam filter.

If you trust the sender, put them into your address book. Then this message wouldn't (shouldn't) be classified as Junk.

If you don't know the sender, how likely is it that the message has any content of value to you? Particularly if it is all image and no text? Reputable senders know better than to use this format.

I know the sender, can't you read? I have set his mails to go to junk because they send too much mail, but I check from time to time their junk mail for thing I may be interested in. Real estate senders send images of houses they want to sell, I think you do not know what you are talking about. Please do not reply anymore, I'll seek help from Mozilla.

You can try not to move those messages to Junk and see if you do see the images when opening the message in Inbox in the first place.

In the inbox, I can click show contents and see what is in. In the JUnk folder, you can only send it back to inbox if you want to see contents. That is what is wrong, people should be able to see the contents, so that many mails are not send back to inbox confusing spam mail training. You can put the usual stupid warning of impending catastrophe if mail contains virus.

Excuse me. have you read above AND seen the snips of what I see in messages in junk folder? Before replying , please see previous messages.

I think you are misusing the junk controls.

There are many varieties of junk mail. Here is one classification scheme:

1. Malicious in a direct sense (contains malware); 2. Malicious in an indirect sense (takes you to a malicious website); 3. Just a nuisance that you don't need or want to read, but presents no real threat.

Other types are described and discussed here: https://en.wikipedia.org/wiki/Email_spam

The Junk folder is really for types 1 and 2. It gives you a sandbox where potentially dangerous emails can be stored safely, inspected if needs be, and easily deleted. I actually use my Junk folder for messages that I might want to report. Whether or not reporting services such as spamcop, abusix, knujon etc do any good is a different discussion. And bear in mind that some other email providers' email scanners also use the Junk folder (I'm thinking outlook.com here) so not all that goes into Junk was put there by Thunderbird.

The US government runs a reporting system, via the FTC. They use the term "UCE" - unsolicited commercial email. https://www.consumer.ftc.gov/articles/0038-spam

Your messages from your realtor are not UCE. Whilst they are commercial in nature, you have at some point handed them your email address and expressed an interest in their wares. So these messages are almost certainly not "unsolicited". They fit into my category 3. They are not malicious, they intend you no harm, but they are of little value or interest. They do not belong in your Junk folder, since you apparently do wish to read them, even if only occasionally.

Yes, I get many messages from services such as expedia, lastminute.com, bookings.com etc because I used them once and needed to submit an email address to make use of them. So they are "solicited" not "unsolicited". I have the power to unsubscribe, but then I'd probably have to go through the same loop if I ever wanted to use them again. So I accept their largely useless mail, but filter them to their own folder where they are out of sight and out of mind. But they are not Junk, in that they do not deserve to be reported to an anti-spam service. As with your realtor, I actually asked (at some distant point in time) for these messages to be sent to me.

If you need to check the content of a message you have several choices.

If you do want to see a message from the realtor then there's no harm in moving it to another folder that permits viewing its contents. This message is not really junk, is it, so you won't do any harm to the Junk Controls and their scoring scheme. If it turns out to be real junk, let's hope nothing nasty got out, and just delete it or put it back into Junk.

You could use ctrl+u to see its "source". Learn how to read the headers so you can decide if you trust where it says it came from.

My own most persistent junk mail is a steady stream of stuff about retirement apartments, SUVs, condominiums, walk-in bathtubs, health insurance, medicare, garage floor coverings, water purification etc. It's obviously junk because it is littered with Americanisms that stand out to me as a British English speaker. And the prices or promised savings are in USD. ;-) What intrigues me about these is that Thunderbird is almost entirely incapable of learning that they are junk. The spammers who designed these have done a very good job in evading our heuristic learning tools.

"I know the sender, can't you read? I have set his mails to go to junk"

So of course they are treated as toxic waste. Your choice. But I'd say the Junk Folder is not appropriate for messages where you know the sender.