Upscale images without losing detail — on your Mac
Enlarge a photo to four times its size and keep the detail that a normal resize throws away. Upscale runs Real‑ESRGAN directly on your Mac's GPU — no upload, no queue, no watermark, and no credit counter ticking down.
What "upscaling" actually means here
Dragging a corner in Preview stretches the pixels you already have, which is why an enlarged photo goes soft and blocky. Real‑ESRGAN does something different: it reconstructs detail that the small version implies — edges stay sharp, texture stays texture, and text in a screenshot stays readable.
It is most useful on the images you cannot reshoot: an old family photo, a product shot that only exists at thumbnail size, a logo someone sent you at 400px, a frame grabbed from a video.
Two models, because photos and drawings are different problems
- Photo —
realesrgan-x4plus, tuned for photographic detail, skin, foliage and noise. - Anime —
realesrgan-x4plus-anime, for illustration, animation and flat-colour artwork, where the photo model tends to invent texture that should not be there.
Both are the official xinntao weights rather than community retrains, so the results match what the published model is known to do.
What it handles
- Input — PNG, JPG, WebP, BMP, TIFF and HEIC.
- Output — PNG for maximum quality, or JPG when you need the file smaller.
- Scale — 2× or 4× the original width and height.
- Batches — drop in a folder and Pro works through the queue in order.
Lite and Pro
Lite ships inside the free Rude Dog hub: 2× upscaling, one image at a time, using the same engine and with no watermark. The cap is on throughput and scale, never on the quality of what you get out.
Pro unlocks 4×, the anime model and batch queueing for £29 paid once. Renewing the update window later costs £15 and is optional — the version you bought keeps working either way.
Comparing the options
The best free image upscaler is genuinely excellent, and we say so. We wrote up the whole field — including where Upscale is and is not the right choice.
Requirements
A Mac running macOS. The engine ships inside the app, so there is no model to download before your first image and no internet connection required to run one. Upscale is signed and notarised by Apple, and installs through the free hub.
The other Rude Dog tools
- Transcribe — audio and video to text, offline
- Cutout — remove backgrounds, down to hair and fur
- Interpolate — double or quadruple a video's frame rate
All four are covered by the Suite licence, and every one ships a free Lite tier inside the same hub download.
Questions
Does it upload my images to a server?
No. Real-ESRGAN is bundled inside the app and runs on your own GPU. Images are read from disk and written back to disk, with no upload step, no queue on someone else's hardware and no account required to process a file. It works with the network switched off entirely.
Is there a watermark?
No, and not in the free tier either. Lite is limited on scale and on batching, never on the output itself — what comes out is a clean image in both tiers. There is no stamp, no logo, and no reduced-quality preview that you have to pay to unlock.
How much bigger can it go?
Up to 4× the original width and height, so a 1000×1000 image becomes 4000×4000 and a 1920×1080 frame becomes 7680×4320. Lite upscales at 2×. Because both dimensions scale together, a 4× pass produces sixteen times as many pixels as the original image.
Which model does it use?
Real-ESRGAN, using the official xinntao weights: realesrgan-x4plus for photographs and realesrgan-x4plus-anime for illustration and animation. No community retrains are bundled, so the output matches what the published models are documented to do rather than someone's unverified fine-tune of them.
What files can it open?
PNG, JPG, WebP, BMP, TIFF and HEIC on the way in, which covers both iPhone photos and most design exports. You can save the result as PNG when you want maximum quality, or as JPG when the file size matters more to you than the last few percent of fidelity.
Can it do a whole folder at once?
Pro queues a batch and works through it in order, one job at a time, so a folder of images can be left running while you do something else. Lite handles a single image at a time — the same engine and the same output quality, just without the queue.
Is it a subscription?
No. £29 once, and that version is yours permanently — it keeps working after the two-year update window closes. Renewing for £15 only re-opens access to newer builds; it is never required to keep using the version you already bought.