This is not the only time this has happened. It seems to happen about 50% of the time when I try to post an image with my tweet. I've had them failing to post for a week and more before I get fed up and delete them. Sometimes it works and sometimes it doesn't.
I am amazed that Twitter floated itself on the stock market. One would have thought that a fully functioning product was essential to stock market floatation when a company only has one product. Apparently not. I'm glad I never invested any money in something that could well be a disaster area.
I can't really see where Twitter is going. It was a service developed to connect to mobile phones with purely text messages. Now it has developed a little further with smart phones but it's still a very rudimentary messaging service that's absolutely plagued by spam and autonomous websites. It's not a serious business tool. It's mostly used by kids that want to post obscene messages. I use it solely as a quick way of posting short updates to my website or interesting curiosity factoids. Frequently it's utterly banal photos of what I had for lunch.
To tell the truth, I'm not really sure what I'm doing with Twitter. I'm trying to promote my website a bit and trying to use it as a contact page. It did work as a contact page recently so that's not too bad. The general purpose of Twitter is a bit lost on me. It seems to be somewhat vague about what it's actually for - what solution it provides to which problem.