Twitter calls them tweets, but in programming terms, they are objects.
Objects have attributes. If an object has a picture attached to it, that should not be represented as part of the text attribute of the object. There should be a separate attribute for each picture. Yet, totally for historic reasons, that's how it works in Twitter.
Note that in the API they are objects. It's just in the UI that they aren't. That seems wrong.
When Twitter was invented we already had conventions for embedding addresses in text. They are called hyperlinks. I think Twitter's designers should decide if they want to have hyperlinks, and if so they should support them the way the web does. There was no good reason to make it work differently. I guess at the time Twitter had problems scaling their servers, so that's where their attention was focused. But those days are behind us.
Seriously, the onboarding process of Twitter is made more difficult and confusing for people because of all those URLs dangling all over the place. When showing a non-technical user Twitter you have to tell them to ignore those things. Or try to explain why some tweets have two URLs and what they mean. It's 2015. It's almost ten years. Wouldn't it be great to finish this product, really, before it turns ten?
Make images an attribute (actually in some cases I think they are). Or allow text to be hyperlinked. Even better: do both.
And while you're at it, let us put more than 140 chars in a tweet. Yes I know the drill, it's supposed to be better if people are forced to be concise. To which I say "Have you looked at your timeline recently?" There are lots of ways to not be concise, and people are using all of them. Give it up. It's over. And btw there are plenty of important, good ideas that require more than 140.
Another thing: It should be easy to ask Twitter what a given hashtag means. If necessary use Mechanical Turk to implement this. In this area, Twitter is mysterious and difficult for newbies and experts alike. These are easy fixes. At some point Twitter stopped improving. Use some of the resources you have to fix them! It's long overdue.
Hashtags are not some obscure technical artifact, as they were when Twitter started. They are now part of human language. Look at ads on buses if you don't believe me. I think baseballs have hashtags on them now!
If Twitter made hashtags easy people would cheer hooray! when Dick Costolo walked into a room. (Not that they don't already.) Hey you could even make the definitions funny.