Free tool · 100% on-device · zero upload
Test if two progress photos actually line up.
Load two photos into the viewer. Drag the ghost opacity slider, wipe across the split, or switch to the difference map to spot drift in camera height, distance, or angle.
Slide the opacity to 50%. If the background walls, shoulders, or landmarks double up, the camera position shifted between sessions.
Catch alignment drift before the photo is taken
Fixing misaligned photos in post-processing causes blurry pixel resampling and aggressive cropping. SameShot draws your previous photo faint in the viewfinder so your shots align perfectly at capture time.
Frequently asked questions
Does this tool upload my photos to any server?
No. The alignment checker uses your browser’s local FileReader and Canvas APIs. The images remain in your computer or phone memory and are never transmitted over the network.
What is the Difference Map mode?
The difference mode subtracts pixel values between Photo A and Photo B. Completely aligned, unchanged background pixels appear pitch black, while mismatched edges, perspective shifts, and body changes light up brightly.
How can I fix drift in future photos?
Drift cannot be cleanly fixed after a photo is taken without cropping or artificial resampling. The reliable solution is capture-time alignment—using a ghost overlay camera like SameShot to align your live viewfinder against the previous photo before pressing the shutter.
What are the most common causes of photo misalignment?
The three most common causes are: standing 2–4 inches closer or farther from the lens (focal perspective shift), tilting the phone up or down, and lighting from a different direction.