Four Months After Coming Home to Hangzhou
On April 3 this year, my girlfriend and I returned to our little home in Hangzhou after a 234-day, 39,580-kilometer journey around China. One thing began immediately and naturally: cooking at home. Four months later, what had we gained? A different delicious meal every day at only one quarter to one fifth of the cost—and, more importantly, healthier bodies. I had lost a full 20 kilograms, and even my already-light girlfriend had lost more than 5 kilograms.
Why I Built SelfieDiary
That was when I suddenly felt regret—not about cooking at home, of course, but about failing to record the change. It was the biggest drop in my weight in 20 years; I was even lighter than I had been in high school. At my girlfriend’s suggestion, I built SelfieDiary to record daily changes.
You might ask: if the goal is to track change, why not simply take one photo a day with the Camera app? What does this app do that helps you keep going?
Make One Photo a Day Hard to Forget
First, there is the calendar. It clearly shows which days have a photo and which do not. My first version used yellow and green dots. My girlfriend suggested showing each day’s thumbnail instead, and it immediately became much clearer. Together with reminders at a time you choose, taking one photo a day becomes something you are less likely to forget.
The Reward for Keeping Going Is Seeing the Change
Is there any reward for taking a selfie every day? The answer is hidden in the record itself. Once you have photos from at least two days, the Change view begins joining them into a continuous transformation video—the kind of face-changing sequence seen in films such as Everything Everywhere All at Once and in striking short videos. Imagine what the result could look like after a full year.
More Than One Face, More Than One Kind of Change
One day, a friend who practices rock climbing told me that one photo was not enough. She also wanted to track changes in her back and biceps. So I built multiple calendars, each with its own check-ins. I use them to record changes in my hair (sadly) and photos of the two of us together.
Bring Old Selfies Into the Timeline
To get feedback sooner, I added a way to import older selfies. I discovered that most of my old selfies were actually group photos with different people—which, as a man, was not entirely surprising. Even so, after the pupil-alignment algorithm processed them, the resulting video amazed me. It was genuinely fun to watch.
Make the Next Photo Easier to Align
The change video uses pupil alignment and fitting, but guidance while shooting still matters: similar framing preserves more of each photo. I first drew a chin guide, but it only worked well for one person and one face. Then I tried outlining people with Apple Vision, with mixed results. Once again, my girlfriend had the better idea: why not use the previous photo as the guide? I made it translucent with a gentle breathing effect, so almost any kind of photo can be aligned with the one before it for a better composite.
Recording Slowly Became a Ritual
I have now been using the app myself for more than a month. During that month I lost another 2.5 kilograms, although the difference is less obvious in photos than the earlier 20-kilogram change. Still, recording myself—and recording photos of my girlfriend and me—has become a ritual. I cannot wait to see what a full year looks like.
In mainland China, search the App Store for ‘自拍日记.’ In other regions, search for ‘SelfieDiary.’
Multiple calendars and custom watermarks are subscription features, priced in mainland China at ¥8 per month or ¥68 per year.
