Private, offline AI upscaling on a Mac: no uploads
Vendor pages checked on November 9, 2026. Local Upscale Studio is in development.
Many AI upscalers work in the cloud. You upload a photo or video, a server enlarges it, and you download the result. That is convenient, but your file has left your Mac, and what happens to it next depends on someone else's policy. A Mac with Apple silicon is fast enough to do the same job itself. This guide explains how to tell whether a tool really works on your Mac, and which Mac upscalers say they do.
Why people keep upscaling local
- Family photos and home videos. Children, old relatives, private moments. Many people would rather not send these to a company they know little about.
- Client work. Photographers, editors and agencies often handle material they don't own. A contract may say where it can be stored or processed.
- Work under an NDA. Unreleased products, internal documents and footage before launch.
- Large files. An hour of video can be many gigabytes. Uploading it, and downloading a larger copy back, takes time on an ordinary connection.
- No credits to run out. Cloud services usually charge per image, per minute of video, or through monthly credits. Work on your own Mac costs nothing extra.
How to check whether a tool runs on your Mac
"Private" and "secure" on a product page don't tell you where your file goes. These checks do.
1. Read the privacy policy
Search the policy for upload, server, store, retain and train. A tool that processes on your Mac usually says so plainly. A cloud service has to describe what it collects, how long it keeps it, and whether it uses it to improve its models. Check that the policy covers the app you're using. Some companies offer a desktop app and a web service, and the policy may describe only one of them.
2. Look for accounts and credits
Signing in, a credit balance or a "cloud" switch are signs that some work happens on the vendor's servers. They aren't proof: an app can need an account only for its licence. But they tell you to look more closely.
3. Turn Wi-Fi off and try it
This is the simplest test, and the most convincing one.
- Open the app and let it finish downloading any models it needs.
- Turn Wi-Fi off from the menu bar, and unplug any network cable.
- Upscale a photo, and a short video if the app does video.
- If it works and the result looks the same as before, that model runs on your Mac.
Test every mode and model you plan to use. Some apps run some models locally and send others to the cloud.
4. Watch the network while it works
With Wi-Fi on, open Activity Monitor (in Applications > Utilities), click the Network tab, and watch the app's "Sent Bytes" while it upscales a large file. A few kilobytes is normal for update checks. Hundreds of megabytes while it works on a video means the file is going somewhere. For a closer look, LuLu is a free, open-source firewall that asks you before any app makes a new outgoing connection.
What Mac upscalers say about where they process
This table reports only what each vendor's own pages say. We have not tested these apps' network behaviour ourselves.
| Tool | What the vendor says |
|---|---|
| Local Upscale Studio | Photos and videos are processed on your Mac and never uploaded. No account, no analytics. Details below. (In development.) |
| Topaz Gigapixel | Both. "Your files never leave your computer with local rendering." Cloud rendering is also offered to "take the pressure off your hardware". On the Personal plan the Wonder 1 model is listed as cloud access. |
| Aiarty Image Enhancer | "Processing runs offline on your device", with "no need to upload your photos to the cloud or any server". |
| Upscayl (desktop app) | Its readme says it needs a Vulkan-compatible GPU to upscale, because the models run on your computer's graphics chip. Version 2.15 added an option to share stats such as GPU model, and an option to turn off update checks. The Mac App Store listing says "Data Not Collected". |
| Upscayl Cloud | A separate web service. Its privacy policy lists "Images you upload" among the data it collects, and says your images are not used to train AI models. |
| Real-ESRGAN (command line) | A portable program that includes its models. We ran it with network access blocked and it worked normally. See how to run Real-ESRGAN on a Mac. |
| Pixelmator Pro | Has Super Resolution upscaling. The Apple pages we checked don't say where it runs, so try the Wi-Fi test above. |
Quotes are from the vendors' pages on November 9, 2026. Policies change; check the current version before you rely on one.
Exactly what Local Upscale Studio sends
Studio is a pay-once Mac app for photos and video, for Apple silicon. Both modes run on your Mac: Fast mode uses Real-ESRGAN, and Quality mode uses SeedVR2 for photos and FlashVSR for video. Here is everything that leaves your Mac, taken from our privacy policy.
What never leaves your Mac
- Your photos and videos. They are never uploaded to us or to anyone else.
- What you do in the app. There is no analytics or advertising code and no tracking.
- Your identity. There is no account to create.
What does use the internet
- Model downloads. If the app downloads extra model files after you install it, those downloads contain no information about your photos or videos.
- Buying. Checkout is run by a merchant of record, a payment company that handles card payments, sales tax and VAT. It shares your name, email address, country, order details and licence key with us so we can deliver the app and support you. We never see your full card number.
- Licence keys. The current app doesn't check your key online. If a later version does, it will send only the key and an anonymous identifier for your Mac, and we will update the privacy policy first.
This website is separate from the app. It sets no cookies and counts visits with Cloudflare Web Analytics, which doesn't use cookies either.
When Studio ships, please run the Wi-Fi test on it yourself. That is the point of the test: you shouldn't have to take our word for it.
What you give up by staying local
- Speed depends on your Mac. A cloud service runs on large server GPUs. Fast mode is quick on any Apple silicon Mac, but Quality video is slow and needs a Mac with plenty of memory.
- Disk space. Local models have to live on your Mac, and the newer ones are large.
- No upscaling from your phone. A web service works from any browser; a Mac app works on the Mac.
You can see how the local models look, with speeds measured on our M5 Max development Mac, on the SeedVR2 and FlashVSR results page.
Questions
Is a desktop app always private? No. A desktop app can still upload files, for cloud models or for features that run on a server. Check each mode with the tests above.
Is offline upscaling slower? It depends on the Mac and the model. Real-ESRGAN runs quickly on any Apple silicon Mac. The newer diffusion models took 10 to 30 seconds per photo on our M5 Max development Mac, and far longer per minute of video.
Can I upscale video offline too? Yes, if the app runs its video model locally. See how to upscale video to 4K on a Mac and old home videos.
How much does Studio cost? $49 once at launch, then $79 at version 1.0. No subscription. See pricing and what other upscalers cost.
Guides: how to upscale photos on a Mac, a pay-once Topaz alternative, Gigapixel alternatives.
Sources
- Topaz Gigapixel: topazlabs.com/gigapixel
- Aiarty Image Enhancer: aiarty.com/ai-image-enhancer
- Upscayl: github.com/upscayl/upscayl, v2.15.0 release notes, Mac App Store listing
- Upscayl Cloud: upscayl.org/cloud, privacy policy (last updated August 31, 2025)
- Pixelmator Pro: apple.com/pixelmator-pro, Mac App Store listing
- LuLu: objective-see.org
- Real-ESRGAN: github.com/xinntao/Real-ESRGAN
- Local Upscale Studio: privacy policy
Topaz Labs and Gigapixel are trademarks of Topaz Labs. Mac, Pixelmator Pro and Activity Monitor are trademarks of Apple Inc. Aiarty, Upscayl, LuLu and all other names are trademarks of their owners. Local Upscale Studio is not affiliated with any of them.