This Tuesday Twitter announced new update in home feed. Now you'll see image and video previews without clicking on show button. This update is also available to android and iOS users who updated their app.
Before this update you had only long list of text based tweets in your feed from people you are following. You used to put some awesome pictures on twitter but only some people clicked show button to get preview of pictures, but now twitter wants to get your followers closer to you and your stuff so they turned text pages into colorful pages with lots of fun pictures. Images and video previews are for media hosted on twitter servers. Video shared from vine'll also get automatic preview.
There are people like me who really appreciate this update but there are some people who didn't like this update. Most of the people who didn't like this update are giving reason that if someone put some sensitive or odd content over twitter they'll get that in their feed too, and it is really embarrassing to have this content if you are browsing twitter with someone in your room.
Filter out sensitive media for desktop version:
I want to give little suggestion for getting you secured and my suggestion is don't follow such people or go to twitter settings and find Do not inform me before showing media that may be sensitive. Make sure it is unchecked. Now you'll not get sensitive media or pictures previews automatically.
Block photo and video previews on mobile app:
If you've updated your mobile twitter application and you are seeing picture & video previews automatically but you don't want then get in app settings and find out Image previews and uncheck it. From now on you'll not get image or video previews automatically.