Every feature, explained plainly

Camera or upload

Tap Camera and SkinLogs opens your phone's own camera app rather than a preview built into SkinLogs, so you get your phone's normal focus, flash, and framing controls. Tap Upload photo instead to pick something already in your library. Either way, you end up on the same preview screen before anything is saved.

An optional note

Before saving, there's a single-line field, "Add context to save with this scan", entirely optional. Nothing else is asked. There is no form to fill in about symptoms or severity here; that lives in Diary instead.

What happens when you save

• The photo is resized and compressed for storage. That resized copy is the only one kept, and it's the same file used everywhere the photo appears later: your history, Compare, and the full scan view.
• If you picked a closest skin tone match during setup, a small brightness and contrast adjustment is applied so exposure looks more consistent from scan to scan. It's a fixed lookup table, not anything that changes what the photo shows.
• A photo you upload is automatically checked for obvious blur or low light, so you can retake it right away instead of finding out later.
• Everything happens on your device. Saving a scan never sends it anywhere.

Marking up a photo afterward

From a saved scan, "Annotate photo" opens a plain freehand drawing tool: pick one of five colors and draw directly on the photo to point something out for your own reference. There's no shape tool and nothing is detected or suggested automatically. Reopening annotation always starts from the original photo, so your notes never stack on top of each other.

What a folder actually is

Just a name and, if you want, a general location like "left forearm". Any scan can be assigned to one folder. There's no limit on how many folders you keep.

Rescan reminders

Each folder can have a reminder set to weekly, every two weeks, monthly, or every three months, or none at all. This schedules a real notification on your device at that interval, not just a badge inside the app.

Folder suggestions

When you save a new scan without saying which folder it belongs to, SkinLogs compares its photo to your existing scans by visual similarity and, if one looks like a close match, offers to file the new scan alongside it. You can accept the suggestion or dismiss it and file it yourself; it's a starting suggestion, never automatic.

Search

A search box over your folder names and locations, and a separate one over your full scan history, both plain text matching, nothing fuzzy or AI-assisted.

Progress report

From any folder, generate a PDF that pulls together its photos with a short summary: how often you've been scanning and the typical gap between scans, your treatment completion rate over the last 90 days, and any standout patterns from your Diary entries for that area. Every number in it is arithmetic over your own local data. Nothing about it is AI-generated or sent anywhere to produce.

Choosing your two photos

Tap either photo row and a screen of thumbnails opens, so you can recognize the scan you want by sight instead of guessing from a date. The scan already chosen in the other slot is grayed out, since the same photo can't fill both sides. A back button always lets you close the picker without being forced to choose.

Slider or overlay

• Slider: drag a handle across the screen to reveal more or less of one photo underneath the other.
• Overlay: both photos sit on top of each other, and a slider adjusts how much of the earlier one shows through, a manual opacity blend.

Both modes are pure visual comparison. There's no image analysis running behind either one, no highlighting of "what changed", and no verdict given. You decide what you're seeing.

Exporting

Save the comparison you've set up as a single image, useful for keeping or sharing outside the app.

The body map check-in

Tap any spot on the body diagram to mark it as affected today. For each spot marked, log roughly how much of that area seems affected, how severe it feels, and how itchy it is, then tag any treatments you used there. Marking a spot again tomorrow builds a history for that exact location, separate from every other spot you're tracking.

Triggers and what helped

A fixed list of common triggers (stress, weather, a new product, and more) and things that helped (moisturizer, a cool compress, and so on), each tappable, plus room to add your own custom tags. These get logged alongside that day's severity so patterns can surface later.

Patterns and Routine impact

Once you've logged enough check-ins, both with and without a given tag, a Patterns card shows the average severity on days with that tag versus without it, so you can see whether it seems to line up with better or worse days. A separate card does the same for Routine adherence: full-adherence days compared with partial-adherence days. Both are plain averages over your own logged entries, shown with a note that they're not a statistical or medical conclusion, and never a diagnosis.

Voice memos and search

Attach a short voice memo to any day's check-in and play it back later. Past entries are searchable by their notes, and filterable by tag, so a specific day is easy to find again.

A weekly check-in, if you want it

An optional, separate quality-of-life section asks a handful of personal questions about how the week affected you. It's collapsed by default, meant to be filled in about once a week rather than daily, and isn't modeled on or scored like any licensed clinical instrument.

Adding a treatment

Give it a name, how often you use it, and any notes. A few common starting categories, like moisturizer or sunscreen, are offered as shortcuts, or type your own from scratch. Tag it to whichever body areas it applies to so it's easy to see at a glance where it's used.

Reminders, on the days you actually want them

Set a daily reminder time, and if a treatment isn't a daily thing, restrict it to specific days of the week. Each selected day schedules its own real device notification.

Today's checklist

Every active treatment shows up with a one-tap checkbox and a 7-day history strip, so you can see at a glance whether you've been keeping up. A running completion rate covers the last 90 days.

Flagging an issue, pausing, and history

Flag something right from the checklist (too greasy, stings, no visible effect, and a few others), kept as a record on that day's log. Pausing a treatment keeps its history intact without counting the paused days as missed.

1. Tag a product to the area it's for

In Routine, tag a treatment to whichever body area it's used on. This is the only setup step, everything after this happens automatically from your normal Diary and Routine logging.

2. Keep logging like you already do

Log your daily Diary check-in for that area (severity and whatever else you track) and check the product off in Routine on the days you use it. No extra step, no separate form, just your existing habit.

3. It compares "with it" days against "without it" days

Once you've logged at least 5 diary days for that area, with some days you checked the product off and some you didn't, Routine Pattern Finder works out your average severity on each side and shows the gap. That's the entire calculation: an average, compared to another average, over your own numbers.

4. A confidence label, so you know how much to trust it

• Early signal: a small gap, from a small number of days. Worth noticing, not worth acting on yet.
• Worth a look: a clearer gap, with a bit more history behind it.
• Consistent pattern: the strongest label, needing the most days and the widest gap before it's shown.

Nothing is shown at all until there's a real sample on both sides, no pattern gets forced out of thin data.

5. Photo evidence, when you have it

If that area has a tracking folder with a couple of scans in it, Routine Pattern Finder pulls the photo closest to your best day and the photo closest to your worst day and shows them side by side, so it's not just a number, you can actually see it.

The calendar

A month view marks which days had a scan, which have a folder reminder due, and which have a check you've planned ahead, all as small dots you can tap into.

Planning a check

Plan a one-time or recurring check for any folder, with your own note and time. Recurring checks keep scheduling themselves automatically so you never have to re-plan the next one by hand.

Stats, streaks, and milestones

Four running numbers: total scans, folders tracked, reminders due, and your current daily logging streak. Milestones celebrate things like your first month of tracking or reaching a number of saved scans, pure counting and date math, never a reflection of how your skin is actually doing.