Click on your name which is there on your left bar.
Click on your profile page and navigate to contributions. There you can see the photo gallery option.Click on that ans see the picture posted by you.
When you click on a particular photo, you can see an edit option just below the picture. On the yellow color bar you can see "Posted date, Posted By, Member level and Edit option.
From that edit option you can change everything.
A S Kranthi Kiran