Upscayl

1. What is Upscayl?

Upscayl is a free desktop app (Windows, macOS, Linux) that enlarges small, blurry or pixelated pictures while keeping them sharp. You pick an image, press one button, and a little later you get a bigger version (how long depends on the picture and your graphics card). Under the hood it uses an AI model (Real-ESRGAN) to guess the missing detail and paint it in, so the result usually looks better than simply stretching the picture.

It stands in for web tools and apps that charge per month or per image to enlarge pictures with AI. Upscayl is open source (AGPL-3.0 licence) and describes itself as a "Free and Open Source AI Image Upscaler".

A good fit if:

• You have old photos, shots from an older phone, or downloaded pictures that are too small, and you want a bigger copy to print or post.
• You want to sharpen illustrations, game art or pixelated screenshots.
• You want to process many pictures in one go without paying per image.

Not a fit if:

• Your computer has no graphics card that supports Vulkan. The project says plainly that it needs one, and many integrated graphics chips (iGPUs) do not work (see section 2).
• Your picture is blurred from camera shake or out of focus. According to the project, Upscayl can improve low-resolution and pixelated images, but it cannot de-blur or fix focus.
• You only use a phone. Upscayl is a desktop app with no Android or iPhone version.

2. What do you need?

• A computer running Windows 10 or later, macOS 12 or later, or Linux.
• A Vulkan-compatible graphics card (GPU). The GPU is the part of your computer that handles graphics; Vulkan is the technical standard Upscayl uses to run its AI on it. The project notes that many iGPUs (graphics built into the processor) do not work, but "no harm in trying". A separate card (NVIDIA, AMD) is usually the safest bet. The documentation does not state a minimum amount of graphics memory, so if a large image fails with a memory error, try a smaller one.
• Disk space: the 2.15.0 installers are about 261 MB (Windows) and about 385 MB (macOS). Leave a few hundred MB free for the app, plus room for the enlarged pictures.
• Internet to download the app. No account, no API key, no cost.

3. Install, step by step

The easiest way is to download the installer from the official site https://upscayl.org or from the GitHub releases page https://github.com/upscayl/upscayl/releases/latest. The latest version at the time of writing is v2.15.0 (published 25 December 2024). File names include the version number, for example upscayl-2.15.0-win.exe.

On Windows

Step 1: Download the installer

On the download page, choose the file ending in -win.exe (about 261 MB). When it finishes, it sits in your Downloads folder.

Step 2: Run the installer

Double-click the .exe. If Windows shows a SmartScreen warning (a "this app is not verified" notice), click More info and then Run anyway, or click Yes if you get an "unverified publisher" dialog. This is the project's own instruction.

Step 3: Follow the installer

Click through the screens until it finishes. When it worked, you can open Upscayl from the Start menu.

On macOS (macOS 12 or later)

Step 1: Download the installer

Choose the file ending in -mac.dmg (about 385 MB). The project also lists the app on the Mac App Store (search for "Upscayl").

Step 2: Drag it into Applications

Double-click the .dmg, then drag the Upscayl icon into the Applications folder.

Step 3: Open it the first time

Open Finder, click Applications in the left sidebar, find Upscayl, right-click it and choose Open. When the warning window appears, click Open once more. After that you can open it normally.

Alternative: Homebrew

If you already use Homebrew (a tool that installs Mac software from the command line), this works:

brew install --cask upscayl

On Linux

The project says Upscayl is in the software listings of most Linux systems, and can be installed through Flathub (Flatpak), Snap, the AUR (Arch) or downloadable packages. The "run it without installing" way:

1. Download upscayl-x.x.x-linux.AppImage from the download page.
2. Right-click the file, open the Permissions tab and tick the box that allows it to run as a program.
3. Double-click the file to run it.

There are also .deb (Debian, Ubuntu), .rpm (Fedora) and .zip packages.

Note: On Linux, if the app does not detect your graphics card, install the Vulkan drivers for your card (see section 5).

4. First use

The app is in English, and button names can differ slightly between versions.

1. Open Upscayl and select the image you want to enlarge. It appears in the middle panel.
2. Pick an upscaling style (an AI model) from the drop-down list. The current version ships with 7: Upscayl Standard, Upscayl Lite, High Fidelity, Remacri, Ultramix Balanced, Ultrasharp and Digital Art. Beginners should start with Upscayl Standard, then try the others on the same picture to see which suits it. "Lite" suggests a lighter version and "Digital Art" suggests drawn artwork, but the documentation does not describe them in detail, so test them yourself.
3. Choose an output folder for the results.
4. Click Upscayl to start. A progress bar runs, and when it is done the new image is in the folder you chose.

What a good result looks like: the new image is larger (four times the width and height with the 4x models), with edges, text and textures sharper than the original. Open both pictures side by side to compare.

Good to know:

• The built-in models are all 4x. Since version 2.8, the 1x, 2x and 3x options are made by enlarging 4x and scaling the result back down, so they still work.
• There is a mode for whole folders of images (batch). Do not stop a batch halfway: according to the project, if a model does not support a step, the app finishes enlarging all the images first and post-processes them afterwards, so just wait.
• Settings has a GPU ID field for choosing which graphics card to use (for example 0, 1, or 0,1). If you have both a separate and an integrated card, pick the separate one.
• To add more upscaling styles, the project keeps a community model collection at https://github.com/upscayl/custom-models.

5. Common problems and fixes

Sign	Cause	Fix
Clicking Upscayl does nothing, or you get a Vulkan error	The graphics card does not support Vulkan, or its driver is too old	Update your graphics driver to the latest version. The project's troubleshooting page says that for VK_ERROR_INCOMPATIBLE_DRIVER you should check your drivers very carefully
The app uses the wrong (weaker) card	You have several cards and it picked the wrong one	In Settings, set GPU ID to the number of your separate card. On Windows, turn on performance mode for the app, otherwise the system may override your choice
Out-of-memory error (VK_ERROR_OUT_OF_DEVICE_MEMORY)	The image is too big for the card's memory	Try a smaller image, or cut the image into parts and process them separately
Colours in the result look off	Upscayl currently supports only the sRGB colour profile	Convert the image to sRGB in a photo editor before enlarging
The result looks almost the same as the original	The original is blurred or out of focus, which Upscayl cannot fix	Use pictures that are small or pixelated, not ones blurred by focus
macOS refuses to open the app	Apps downloaded outside the App Store are blocked the first time	Use the first-launch method in section 3 (right-click, Open). If it still fails, update macOS to the latest version
The app will not start or runs strangely slowly	A temporary glitch	Restart the computer. If it persists, reinstall the latest version
Linux does not detect the card	Vulkan drivers are missing	Install the Vulkan drivers for your card's maker. For Intel on Arch Linux, the documentation mentions the vulkan-intel package

For anything else, see the official troubleshooting pages: https://github.com/upscayl/upscayl/wiki/Troubleshooting and https://docs.upscayl.org/.

6. Uninstall / update

Update: download the newer installer from https://upscayl.org or the Releases page and install over the old one. With Homebrew, use brew upgrade --cask upscayl. If you installed from Flathub, Snap or the Mac App Store, update through that store.

Uninstall:

• Windows: open Settings > Apps > Installed apps, find Upscayl and click Uninstall.
• macOS: drag Upscayl from Applications to the Bin. If you used Homebrew:

brew uninstall --cask upscayl

• Linux: delete the AppImage file, or remove the package the way your store does it (Flatpak, Snap, apt, dnf).

The pictures you made live in the folder you chose, so removing the app does not delete them.

7. Frequently asked questions

Does it cost money? No. The app is free and open source under AGPL-3.0. The project has a donate button, but it is optional.

Do I need internet? To download the app, yes. According to the project, the enlarging runs on the graphics card in your own computer. The documentation has no dedicated privacy statement, so if your pictures are sensitive, check for yourself by disconnecting from the internet while you try it.

Will it run on a weak machine or without a separate graphics card? Not guaranteed. The project says a Vulkan-compatible card is required and many iGPUs do not work, but you can try, since it costs nothing.

Does AI enlargement make a picture "more real"? The model guesses the missing detail, so what it adds is a guess, not real information from the original. For pictures used as evidence or records, keep the original.

Can I use it from the command line? Yes. The project's command-line tool is called upscayl-ncnn (https://github.com/upscayl/upscayl-ncnn), meant for people comfortable with programming.