You can use watermarking to ensure that your images are not misused or claimed by others. Making a watermark is a very easy procedure in Photoshop.
Open your picture and then press F7. A layer window will open. Add a new blank layer using the Create a new layer option at the bottom of the window. Go to the main tool bar on the left side to Text tool (indicated by a T sign). Type out what you want your watermark to say. You can choose different colours by clicking on the Set Background Colour tool (two intersecting boxes). After typing out your text (you get options for small or big, bold or smooth fonts), go to Layers, click on opacity to choose the desired level of transparency of your text. Then go to Layer at the top of the page and choose Flatten Image. The text becomes a water mark on your image.