Multiplicity Photoshop. Probably my best Photoshopped picture. There is also a YouTube link that can help you I will add at the bottom of the page. I did this photo a while ago so here’s a link to get some easy to follow step (this is the page I used while making it).
Step 1. Use a tripod, when possible, to make your life easier once you get to the editing steps. This will keep all of your images lined up making the blending easier. I did not use a tripod but I will show you how I compensated for this in Photoshop.
Step 2. Ideally, shoot in manual in evenly lit location with consistent lighting. Make sure the only thing moving is your subject. Have your subject move around in the frame striking various poses to create more interest. Snap pictures in each location. Get creative with the posing like jumping in the air, doing a handstand, etc. You can even have them pretending to look at themselves. Kids love doing this! I would recommend at least 3 – 10 poses.
Step 3. Once you have all of your images loaded onto your computer, open Photoshop. Select FILE>Scripts>Load Files into Stack. This step will bring up a window where you can browse for your images. Select all the images you just created. If you did not use a tripod like me, then check the box that says “Attempt to Auto Align.” Photoshop executes a bit of magic here and usually does a great job lining up all the images for you. But again, you should use a tripod if possible. Depending on how many images you have this step will take a few seconds. When it is completed, all of your images are stacked as layers in one document.
Step 4. Next click on each layer one at a time and add a layer mask to each layer (the layer mask button is the rectangle with a circle in it at the bottom of the layers panel). When you have finished adding them to each layer all of your layers should now look like this.
Step 5. Now select the mask of the top layer in the layers palette. Make sure you are on the white box, not the thumbnail of the image. Once selected it will have a box around it. Using a black soft-edged brush, loosely “erase” the subject. This sounds backwards but trust me it will work. After the subject is completely erased, with the mask selected, use the keyboard shortcut Control + I (PC) or Command + I (Mac) to invert the mask. This last step should reveal the subject you just “erased” and then reveal the subject on the layer just below.
Step 6. Go to the next layer and repeat Step 5. Then, repeat again for each additional layer until all of the different positions are showing. Make sure to look for any possible areas that are not lined up, and if needed use the clone tool to blend them.
Step 7. When you are happy with the result, save a layered .PSD Photoshop file (in case you notice any areas you need to fix later). Then flatten the image and edit. Get ready to amaze your friends and family.