A few months ago my twitter cards were working beautifully for me and they were really easy to set up. Then one day they were suddenly showing up with incorrect formatting, despite no changes at my end. After reading lots of conflicting information I eventually got it all to work again, though I had to change the size of the image and the file name before it showed properly. Then a couple weeks later no image at all is showing in tweets.
When I check the domains on the twitter card validator it all looks correct with a large image summary but when tweeted nothing appears, though on a desktop browser there is a space where the image should be. I've even tried forcing the refresh by changing the twitter card image url to include .jpg?555 so that twitter checks for the actual image, but even that isn't working.
It all seems to be terribly hit and miss, but more usually miss. Does anybody know where I'm going wrong here?
Two urls to check are https://greatwebdesign.uk and https://colourmanagementpro.com