Open both the image with the head you want to use and the image with the body in Photoshop.
Select the Head:
Use the Lasso Tool or Quick Selection Tool to select the head you want to transfer. Be as precise as possible around the edges.
Copy the Head:
Once selected, press Ctrl + C (Windows) or Cmd + C (Mac) to copy the head.
Paste the Head:
Switch to the image with the body and press Ctrl + V (Windows) or Cmd + V (Mac) to paste the head onto this image.
Position and Resize:
Use the Move Tool to position the head roughly where you want it.
Press Ctrl + T (Windows) or Cmd + T (Mac) to enter Free Transform mode. Resize and rotate the head to fit the body. Hold Shift while resizing to maintain proportions.
Blend the Edges:
Add a Layer Mask to the head layer by clicking the Layer Mask icon at the bottom of the Layers panel.
Select a soft brush and paint with black on the mask to blend the edges of the head with the body. Adjust the brush size and opacity as needed.
Adjust Colors and Lighting:
Use Adjustment Layers like Curves, Levels, or Hue/Saturation to match the color and lighting of the head with the body. Clip these adjustments to the head layer by right-clicking the adjustment layer and selecting “Create Clipping Mask.”
Final Touches:
Use the Clone Stamp Tool or Healing Brush Tool to fix any imperfections and make the transition seamless.
Zoom in and out to check for any areas that need more blending or adjustments.
Save Your Work:
Once you’re satisfied with the result, save your image in the desired format.
Tips
Zoom In: Work at a high zoom level for more precision.
Layer Mask: Use layer masks instead of erasing parts of the image. This allows for non-destructive editing.
Adjustment Layers: Use adjustment layers to tweak colors and lighting without permanently altering the image.