PhotoDiff: Before After Photo

See what actually changed between two photos.

PhotoDiff puts one photo next to another taken weeks or months later, lines the two up on the same feature, and lets you slide between them. Skincare, training, hair, getting back on your feet after a procedure — whatever you are watching change, you get to see it instead of guessing.

THREE WAYS TO COMPARE
• Side by side — both photos, same size, same position
• Slider — drag the line across to sweep from the earlier shot to the later one
• Overlay — the photos stacked, with an opacity slider to fade between them

LINE THEM UP PROPERLY
Two photos taken weeks apart are never framed the same way. Mark the same feature in both — drag a box around it, or tap two matching points — and the later photo is mapped onto the first one so it sits exactly where it belongs. If there is a face in the shot, tap “Auto-align by eyes”: the app finds the eyes on the phone itself and places both points for you.

ADJUST IT BY HAND
Move the After photo left, right, up or down, and change its width, height and rotation. Use the sliders, or drag, pinch and twist the photo directly. Match the brightness of the two shots as well, so a change of lighting doesn't read as a change in you.

HIDE WHAT YOU DON'T WANT TO SHOW
A mosaic over the eyes, over the whole face, or over any region you draw with a finger.

MARK IT, THEN SHARE IT
Circle what changed with the pen, then export the comparison as a single image, captioned with the group name and how many days apart the two photos were taken. No watermark.

ONE GROUP PER THING YOU TRACK
Make a group for each person, area or routine — “Nose surgery”, “Skin care”, “Left knee”. A group holds its starting photo and every later photo you add, so one story stays in one place.

STAYS ON YOUR PHONE
No account and no sign-in. Photos are kept on the device and are never uploaded. Alignment and face detection run on the phone, so everything still works in airplane mode.

For anyone following a slow change and tired of guessing whether it is working.