Facebook is a social networking website that allows you to connect with other people on the Internet and share media, such as pictures and photos. When you upload a picture to Facebook, you may wish to place a caption under the picture to allow your visitors to better understand the content of the picture. Even after you have uploaded the picture, you can return to your Facebook photo gallery and write a caption for the image.
Log into your Facebook account.
Click "Profile" from the top menu to view your Facebook page.
Click "Photos" from the left side menu to view your photo galleries.
Click a photo gallery, then click on the photo you would like to edit.
Click the "Add a caption" link located under your photo. A text box will appear.
Type your text into this box, then click "Save." Whenever anyone visits this image they will see what you have written as the description of your picture.