Trouble blogging

Annnnnnnd they're gone again.

Yes, my last post's photos keep disappearing. No, I don't understand why. 

I can edit the post, add the pictures back in (using URLs from postimg, as I have done ever since starting my blog here), and they show up just fine in the preview, and on the post once it's published. Then, after an undetermined amount of time, they all start showing as empty broken images, both on the public post itself and within Blogger when I click to edit. I'm not sitting here every day re-editing pictures into my posts over and over again on the off chance anyone wants to view it before they break and vanish again!

It's ONLY happening on the one post I created with the new Blogger, and the one older post I edited in it, because I moved some pics from one folder to another so their URL changed. The photo on that post which I didn't change, still works, as do all the photos on older posts. So it's a problem specific to the new format Blogger, though quite what would cause a 'picture only works for a little while then dies' kind of issue, I don't know.

I won't bother posting anything else til I can find out what I'm doing wrong, which is a shame cos I have some more customs to share already!

[edit, 13-6-2020]

Ok, so thanks to my friend tipping me off that uploading direct to Blogger might be a way round it, I've done some test posts in drafts and the photos do seem to stay put for more than 24 hours. So I've gone back and edited the troublesome posts. 

It's not a perfect fix to sort all my problems, as there's still issues with the New Blogger interface - firstly, you can't drag and drop the images within a post any more, so it's much tricker to get two small shots to display side by side, and if you decide you want them in a different order, you've no choice but to delete the one you want to move and re-upload it into the new place. Because the second problem is that you're supposed to be able to add in any previously-uploaded-to-blogger photo by choosing it from a sort of gallery folder, only clicking on that folder does nothing on my screen, so I can't access the photos I've uploaded if I wanted to!

Also the formatting is horribly difficult because the left-alignment of text usually doesn't work, and getting it to go left and stay left involves a stupid amount of jiggling it about the page using the photos to bounce off, but I think I've figured out the seven or eight steps required to trick it into actually going where one click used to send it, now!