Here is an illustrated guide to adding your signature to your photographs using Photoshop.
Before you get started, be sure that you have a scanner, a black pen, and a white sheet of paper.
Step 1:
Sign your name a few times with the black pen on the white sheet of paper. Do it a few times to get it exactly how you want it to look on your photographs. Be sure to leave space around each trial so that you can properly crop the one that you want later in Photoshop.
Step 2:
Scan the sheet of signatures into a JPG file on your computer. Be sure to scan the image in at 300 dpi.
Step 3:
Open the scanned file in Photoshop and choose the signature that you want to use. Rotate and crop as needed to get the signature to look exactly the way that you want for your images. Save the result in the JPG format.