The latest TB 128 should support OS X 12.7.6, since it is newer than 10.15.

As for 'making a new tab', I'm not sure what you mean, as that usually refers to a browser. Do you mean you can't open messages or Settings in a tab? Does the same thing happen in safe/troubleshoot mode (hold Option when launching TB)?

There is a version 5.1.3 of the add-on for TB 128:

https://addons.thunderbird.net/en-US/thunderbird/addon/shrunked-image-resizer/versions/

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

sfhowes,

Thanks so much for your patient reply (you didn't say what an idiot I was for asking such a question!). Boy am I embarrassed! I'm relatively new to tabs in Thunderbird as I only discovered the feature when I tried the calendar part of TB for the first time a couple of weeks ago trying to see if it's as good as the MS Outlook calendar which is the best I've tried (Apple's Calendar is pretty useless). Since then I forgot that a tab in TB only comes up when opening the calendar or when requesting that a message or folder etc. be opened in a new tab. Lesson learned!  :)

I'm equally (or even more) embarrassed about the Mac OS question. Somehow in my fevered brain I managed to interpret OS 10.15 as 15.10 (dyslexia?). My only excuse is that the new Mac OS Sequoia is 15.0, so when I saw "15"... Oh well, all sorted out now (except maybe my brain, but then I'm 78! ). :)

And by the way, for some reason or other (I won't try to understand) the Shrunked Image Resizer (SIR) seems to be working again. Thank goodness because as I said in my request for help, it really is a very useful — dare I say indispensable — Add-on, and I'm therefore inspired to ask why such a feature isn't already built into Thunderbird. Might you be able to answer that? If not, I would be grateful if you could suggest who I might contact about it. I'm worried about the SIR Add-on's future because apparently its author, Geoff Lankow (who I believe works or worked for Mozilla) decided sometime ago not to keep updating it, and I'm afraid that one day it won't work with future updates of TB.

Anyway, thanks so much for your quick answer to my ill-informed questions.

Cheers! Chris

Any feature that's provided by a supported add-on is less likely to be built into the core app, as it requires devoting resources that might be better allocated to other concerns. In this case, your best bet is probably to contact the author himself for further information.

If it ever becomes incompatible with future versions, there are many free apps that perform image resizing, at least that is my understanding in the Windows world.

Oh, you're a Windows guy, eh? :) I'm not sure if you are saying that there are many such Add-ons for Windows Thunderbird or you are talking about resizer apps for Windows to be used outside TB. If the former, unfortunately that doesn't seem to be the case on the Mac side of Thunderbird. I've searched through TB's Add-on search function and on the 'net and found only Shrunked Image Resizer. If you mean there are lots of Windows apps that can shrink images outside of TB, of course I'm also able to resize images outside TB using various Mac apps. But it's so very handy to have SIR do it as soon as I attach some jpegs to an email.

On the question of SIR's future, here's what the author, Geoff Lankow, had to say (not sure when exactly) on his Github website https://github.com/darktrojan/shrunked:

"As you can probably tell from the long list of unanswered issues, I clearly don't have time for this. This Github project will now be put in read-only mode. Since 2018 I have been working full-time developing Thunderbird, and even if I did have any spare time outside of work, the last thing I would want to do is maintain more code, especially as it's the same tools and processes as my day job. Thank you to everybody who has supported Shrunked over the years, by donating, translating the text, sending pull requests, or helping others."

I do find it a bit strange that Geoff worked (or maybe still works) with Mozilla developing Thunderbird and didn't get to build SIR into TB. I could try to contact him to ask, although I haven't found a way of doing so. In the meantime, I have to admit that I find how Mozilla does things is all a bit mysterious, for example, a guy who works for Mozilla developing Thunderbird creates a really handy Add-on for it but that Add-on doesn't become an integrated feature of the software he's developing. Hmm...

As for the future of SIR, maybe there's still some hope because someone named "memeler" https://github.com/memeller/shrunked/releases seems to have done some work on SIR in the last while. I'll keep an eye on that website.

So, thanks again for your responses to my pesky questions, and maybe we can leave it at that unless you have some further advice for me.

Cheers! Chris