There are many different ways to add pictures or videos here. You could add media to your own blog / site, add “docs” to groups, and other ways to upload and share pics and videos. The most common way people add pictures and videos (videos must be in mp4 format!) here is to their profile with the media tab.
Hover over your screen name in the top right corner of the screen (Howdy Screen name) – the drag your mouse down to media, click on photos..
this will take you to your profile, and the sub tab for your media. Around the middle of the screen is “Upload Media” – click that.
Once you have found this, there are other ways to get to the same screen, and more ways to add pictures and videos here. I’ll post about other methods at another time.
When you add pictures to your profile via the media tab, they will normally show up in the activity stream that most see on the main site pages.
Adding a picture, video or audio clip to “groups” activity / wall is a bit different. There is a new quick “how-to” on doing that here: How to add pics, videos to groups
How to add pics, videos to groups