✨ Why Sticker?
| |
|---|
| 🖱️ One click | Right-click any image → Open as sticker. No extra apps, no export steps. |
| 🧠 AI-powered | Background removal runs 100% locally on your GPU (or CPU). |
| 👻 Click-through | Click pass-through on transparent layers. |
| 💾 Remembers everything | Close your laptop, reboot, whatever - stickers come back where you left them. |
| ⚡ Instant after first use | The AI model stays warm in a tiny tray app. |
🚀 Get Started
Install the app via winget
winget install Zophie.Sticker
OR grab the latest release
Built from source
> Every release is built in the open by GitHub Actions straight from this source, so you can verify exactly what's in it.
Build from source yourself
You'll need: Windows 11 • .NET 10 SDK • Developer Mode turned on (Settings → System → For developers)
Then just run:
.\setup_modern_menu.ps1
That's it! You'll see "Open as sticker" in your right-click menu on any image file.
> 💡 No Developer Mode? No problem — use the classic menu fallback instead:
>
> powershell > dotnet publish StickerApp\StickerApp.csproj -c Release > .\install_context_menu.ps1 >
>
> The entry will appear under "Show more options" in the context menu.
The first time you create a sticker, the AI model downloads automatically (~180 MB, one-time). After that, everything is instant and fully offline.
To uninstall, run .\setup_modern_menu.ps1 -Uninstall.
> 🧪 Contributing? dotnet test Sticker.slnx builds both projects and runs the unit tests (matte cache-key derivation, tolerant session parsing, the bilinear resize math, and the model registry). CI runs the same on every push/PR, and also checks that the version and the supported-image-extension list stay consistent across the installers and the MSIX manifest.
🎮 Using Stickers
Your cursor needs to be over the visible subject (transparent areas pass clicks through). Here's what you can do:
| Action | What it does |
|---|
| 🖱️ | Drag | Move the sticker around |
| ⬆️ | Arrow keys | Nudge position 1px (Shift = bigger steps) |
| 🔍 | Scroll / + - | Resize (hold Ctrl for fine-tuning) |
| 🌫️ | Shift + scroll | Adjust opacity |
| 🔄 | R / Shift+R | Rotate 15° |
| ↔️ | F | Flip horizontal |
| 👁️ | D / double-click | Toggle between cutout and original |
| 💾 | S | Save cutout as PNG |
| ❌ | Esc / middle-click | Close sticker |
| 📋 | Right-click | Full menu (pin, always-on-top, re-matte…) |
Tray Menu
Sticker lives in your system tray with quick access to:
- Paste as sticker (
Ctrl+Alt+V) — screenshot something, hit the hotkey, instant sticker
- Open images… — pick files manually
- Restore last session — bring back all your stickers from last time
- Unpin sticker — release one pinned (click-through) sticker by name, or Unpin all stickers for the lot
- Clear matte cache… — free up disk by deleting cached cutouts (open stickers and downloaded models are untouched)
- Start with Windows — your stickers are always there when you log in
Command Line
Sticker.exe photo.jpg [more-images...]
Sticker.exe --no-matte logo.png # already transparent, skip AI
Sticker.exe --resume # reopen last session
Sticker.exe --model birefnet-general img.jpg
🧠 AI Models
Not every background removal is perfect on the first try — so Sticker ships with three models you can swap between from a sticker's right-click menu (the "Matte: …" entries):
| Model | Best for | Speed | Size |
|---|
isnet-general-use | Everything (default) | ⚡ Fast | ~180 MB |
u2net_human_seg | People & portraits | ⚡ Fast | ~180 MB |
birefnet-general | Maximum quality | 🐢 Slower | ~900 MB |
Each model's result is cached separately (~/.sticker_cache, keyed by image + model). Switching to a model you've already run loads instantly from that cache — no re-inference; a model you haven't tried yet runs once, then it's cached too. If you ever want a genuinely fresh pass, use "Re-process current (ignore cache)." Set a different default model with --model or the STICKER_MODEL environment variable. Restoring a session brings each sticker back with the model it was matted with when that cutout is still cached; otherwise it falls back to the default, so --resume never triggers a slow re-matte at login.
> 🐢 BiRefNet is heavy. It runs at 1024×1024 through a transformer backbone, so peak memory is several GB and it's much slower than the others. Two things can make it fail with an ONNX Runtime "out of memory" / "Failed to allocate" error even on a capable card:
>
> 1. DirectML is selecting the wrong GPU. This is the most common cause on machines with switchable graphics — see GPU selection in Troubleshooting. Fix that first; it's usually the whole problem.
> 2. DirectML genuinely overflows VRAM. DML's memory planning is less efficient than CUDA, so BiRefNet can need more than its nominal footprint. If you've confirmed the right GPU and it still won't fit, you can shrink the input resolution with STICKER_BIREFNET_SIZE=768 (or 512) to trade some edge detail for a smaller footprint, or accept the retry-on-CPU prompt (same result, just slower). STICKER_FORCE_CPU=1 always skips the GPU.
>
> The lighter isnet/u2net models run at 320–1024 px and rarely hit any of this.
🏗️ How It Works
sticker/
├── StickerApp/ → WPF tray app (the main show)
├── StickerShell/ → Explorer right-click menu integration
└── prototype/ → Original Python version (still works!)
StickerApp is a WPF app where each sticker is a borderless, transparent window with per-pixel alpha hit-testing — your clicks pass through transparent pixels for free. Background removal uses ONNX Runtime with DirectML (GPU acceleration on any DX12 graphics card, automatic CPU fallback). A single tray process keeps the model warm so subsequent stickers open instantly.
StickerShell is a COM server (IExplorerCommand) that puts "Open as sticker" in the top-level Windows 11 context menu — no "Show more options" submenu needed. Registered via a sparse package.
prototype/ is the original Python version (rembg + PyQt6). It shares the model folder (~/.u2net), matte cache (~/.sticker_cache), and session file with the C# app — useful as a test bench or if you prefer Python.
🛠️ Troubleshooting
Common fixes
| Problem | Fix |
|---|
| NU1100 on first build | Your SDK is missing the NuGet feed. Run: dotnet nuget add source https://api.nuget.org/v3/index.json -n nuget.org |
| Package registration fails | Developer Mode is off. Turn it on in Settings → System → For developers. |
| Menu entry does nothing | Set env var STICKER_SHELL_LOG=1, restart Explorer, try again, then check %TEMP%\sticker-shell.log |
| No top-level entry, only "Show more options" | Expected for the .exe/winget install — see Context menu placement below |
| Menu entry vanished after rebuild | Re-run .\setup_modern_menu.ps1 — the registration points at publish\, so don't move that folder |
| Stickers die when terminal closes | Don't use dotnet run — use the published exe (or launch via the context menu) |
| Model download stalls / corrupt | Delete the offending .onnx in %USERPROFILE%\.u2net and re-create a sticker to re-download (downloads are SHA-256-verified, so a corrupt file is auto-rejected) |
| Cutout looks stale after re-matte | Use the tray's "Clear matte cache…" (deletes only cached cutouts, keeps your session + models). Or use "Re-process current (ignore cache)" on the sticker itself. |
| Menu only shows for some image types | Old versions registered the classic menu under the image PerceivedType, which .webp (and others) often lack. Re-run install_context_menu.ps1 / reinstall — it now registers per-extension (.jpg .jpeg .png .webp .bmp .gif). |
| BiRefNet "out of memory" / "Failed to allocate" | Usually DirectML on the wrong GPU — see GPU selection. If the right GPU still won't fit: STICKER_BIREFNET_SIZE=768, take the CPU retry prompt, or STICKER_FORCE_CPU=1. |
| Heavy model fails, then lighter models fail too | Fixed in current builds — a failed session used to hold its VRAM. Update; if on an old build, restart Sticker to clear it. |
| "Start with Windows" won't stick | Check the shortcut exists — see autostart below |
Context menu placement (top-level vs. "Show more options")
Sticker can install its right-click entry two different ways, and which one you get depends on how you installed:
| Install method | Where "Open as sticker" appears | How it's registered |
|---|
.exe installer / winget | Under "Show more options" (classic) | A plain HKCU registry verb |
setup_modern_menu.ps1 (build from source) | Top-level Win11 menu | An unsigned sparse app package (needs Developer Mode) |
install_context_menu.ps1 (classic fallback) | Under "Show more options" (classic) | A plain HKCU registry verb |
Why the difference? Windows 11 only lets an entry into the top-level context menu if it comes from an app package that implements IExplorerCommand (Microsoft deliberately closed the top-level menu to the old registry verbs to stop the Win10 clutter). That package has to be code-signed to install normally — an unsigned package only registers via Add-AppxPackage -Register with Developer Mode on, which is a developer convenience, not something you can ship to end users.
Sticker isn't code-signed yet (solo project, certs are pricey), so:
- The shippable installers (the
.exe and winget) fall back to the classic registry verb → lands under "Show more options". Installs cleanly for everyone, no Developer Mode needed.
- The top-level menu currently only works via
setup_modern_menu.ps1, which registers the unsigned package locally and therefore needs Developer Mode.
This is a limitation of not being signed, not a deliberate choice — both menus launch the exact same app. If/when Sticker ships a signed MSIX (e.g. via the Microsoft Store, which signs packages for you), the top-level menu can be the default everywhere.
If you've installed the .exe and want the top-level entry too, you can run setup_modern_menu.ps1 alongside it; the two registrations are independent (you'd then see both entries until you remove one).
GPU selection (hybrid graphics)
Sticker auto-selects the highest-VRAM adapter for DirectML, so hybrid-graphics machines should use the discrete GPU without any setup. (Earlier builds blindly used DXGI adapter 0 — and whichever GPU drives your primary display is normally adapter 0 — so on switchable-graphics systems they'd land on a low-memory integrated GPU and heavy models would OOM while the real card sat idle. That's now handled automatically.)
If a heavy model still fails with "out of memory" while your GPU clearly has free VRAM, the auto-pick may have chosen wrong — here's how to take control:
Force a specific adapter with STICKER_DML_DEVICE (the DXGI adapter index). Find the index of the GPU you want and set it explicitly — try 1 if 0 is the iGPU:
[Environment]::SetEnvironmentVariable('STICKER_DML_DEVICE','1','User')
Then fully quit Sticker from the tray and relaunch. If 1 is also wrong, try 2, etc. To clear it: set the value to $null.
To check what you're working with, see your adapters and their dedicated VRAM:
Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\*' -EA SilentlyContinue |
Where-Object { $_.'HardwareInformation.qwMemorySize' } |
ForEach-Object { '{0} — {1:N0} GB' -f $_.DriverDesc, ($_.'HardwareInformation.qwMemorySize'/1GB) }
> Note the adapter index can change when your display setup changes. For example, after moving a monitor onto the dGPU, the dGPU becomes adapter 0 — so a previously-needed STICKER_DML_DEVICE=1 would then point back at the iGPU. Clear the variable once the dGPU is your primary display.
Environment variables
| Variable | Effect |
|---|
STICKER_MODEL | Default matting model for new stickers (e.g. birefnet-general). Same as --model. |
STICKER_DML_DEVICE | Override the auto-selected DirectML adapter (DXGI index). Normally unnecessary — Sticker picks the highest-VRAM GPU automatically. |
STICKER_FORCE_CPU | 1 = skip the GPU entirely and run matting on the CPU (slow, but unlimited memory). |
STICKER_BIREFNET_SIZE | BiRefNet input resolution (e.g. 768, 512); lower = less memory, less edge detail. Default 1024. |
U2NET_HOME | Override the model download folder (default %USERPROFILE%\.u2net). |
STICKER_SHELL_LOG | 1 = write Explorer context-menu diagnostics to %TEMP%\sticker-shell.log. |
Where Sticker keeps its files
Everything is per-user, under your profile folder — nothing is written to Program Files or HKLM. Paste these straight into Explorer's address bar:
| What | Location | Notes |
|---|
| AI models | %USERPROFILE%\.u2net | One .onnx per model. Override the folder with the U2NET_HOME env var. Safe to delete — re-downloads on next use. |
| Matte cache | %USERPROFILE%\.sticker_cache | Cached cutout PNGs, keyed per image+model. Prefer the tray's "Clear matte cache…" over deleting by hand — the same folder also holds your session and clipboard captures (the latter auto-pruned to the most recent few). |
| Session | %USERPROFILE%\.sticker_cache\session.json | Positions/sizes of your open stickers — what --resume restores. Shared with the Python prototype. (Don't delete the whole .sticker_cache folder to clear cutouts — you'd lose this.) |
| Shell debug log | %TEMP%\sticker-shell.log | Only written when STICKER_SHELL_LOG=1 is set. |
Registry entries
Sticker touches very little of the registry, and everything lives under HKEY_CURRENT_USER (no admin, no machine-wide keys). Open regedit and paste a path into its address bar to inspect.
Classic context-menu verb (only present if you used install_context_menu.ps1 / the classic fallback):
HKCU\Software\Classes\SystemFileAssociations\image\shell\OpenAsSticker
HKCU\Software\Classes\SystemFileAssociations\image\shell\OpenAsSticker\command
The \command subkey holds the exact launch line ("...\Sticker.exe" "%1") — handy for confirming the menu points at the right executable. Delete the OpenAsSticker key to remove the classic verb by hand.
Modern (Windows 11) context menu is not a plain registry verb — it's a sparse MSIX package registering an IExplorerCommand COM server. So you won't find it under shell\. Instead:
- List it:
Get-AppxPackage *Sticker* in PowerShell
- Remove it:
.\setup_modern_menu.ps1 -Uninstall (or Remove-AppxPackage )
- The COM registration is owned by the package and disappears with it — don't hand-edit it.
Autostart is deliberately not a ...\CurrentVersion\Run key (that location is malware's favourite, so Defender scores writes to it harshly). Instead it's a plain shortcut in your Startup folder:
%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\Sticker.lnk
The shortcut launches Sticker.exe --resume. To toggle it: use the tray menu's "Start with Windows", or just create/delete that .lnk yourself (type shell:startup in Explorer to open the folder).
Deeper diagnostics
- Right-click menu misbehaving? Set the user env var
STICKER_SHELL_LOG=1, restart Explorer (taskkill /f /im explorer.exe & start explorer.exe), reproduce, then read %TEMP%\sticker-shell.log — it traces each IExplorerCommand call.
- Verify the modern package is actually registered:
Get-AppxPackage *Sticker* | Format-List Name, PackageFullName, InstallLocation. If InstallLocation no longer exists (e.g. you moved/deleted publish\), the menu silently breaks — re-run setup_modern_menu.ps1.
- GPU vs CPU matting: Sticker uses ONNX Runtime with DirectML and falls back to CPU automatically. If matting is unexpectedly slow, your GPU path may be falling back — check the tray app's console/output, and confirm a DX12-capable GPU and current drivers.
- Force a model from scratch: delete its
.onnx from %USERPROFILE%\.u2net and clear %USERPROFILE%\.sticker_cache so no stale cutouts are served.
- Full reset (nuke everything user-side): uninstall the app, then delete
%USERPROFILE%\.u2net, %USERPROFILE%\.sticker_cache, the Sticker.lnk startup shortcut, and (if you used the classic menu) the HKCU\...\OpenAsSticker registry key.
📄 License
MIT — © 2026 Zophie
