Why have some jpg attachments disappeared from Trello cards and been replaced by colored squares?

[CJD]

Many of my jpg attachments have been replaced by colored boxes and when I click on them, the photos do not open. They seem to have vanished. It's happening on all my boards in both free and paid workspaces. There isn't any correlation, such as file size or the date originally added to Trello, between the ones that have disappeared. It's very random. Below is a screenshot of part of the attachments section of a card. There should be photos where the brown and green boxes are. I am the only member of some of the boards so it's not because someone else has done something to the photos. I'm using Safari on two different iMacs. I'm also having a similar problem with the Trello app on an iPhone (thumbnails are visible on iPhone rather than colored squares, but photos don't load when I click on the thumbnail.)

[Dreamsuite Mike]

I don't use Apple so can't help too much but I want to help if I can.

Firstly, I recommend using a non-Apple browser (chrome would work)

If you are still having this problem, I recommend you contact Trello Support, who are excellent:

https://trello.com/contact 

[CJD]

Thanks for the suggestion. Unfortunately, I'm having the same problem with Chrome. Perhaps I will have to try contacting Trello support eventually. Thanks for trying to help.