AI image upscaler
Enlarge an image by 2× or 4× with an AI model that runs in your browser. Queue a batch, see the exact output size, and inspect the result at 100% before you save it.
Add images, choose 2× or 4×, inspect the result, then save.
Signed in, typed text and settings save automatically to your private account. Text opened from files stays in this browser’s local storage. Files stay in your browser. Account saving
Add an image to see its exact 2× or 4× output size.
Free · no sign-up · no credits · no watermark. Your image stays on this device. The 4.9 MB model is fetched once from models.floi.dev, then the tool works offline. Read the Real-ESRGAN licence.
How to upscale an image
Add one image or a batch
Drop files on the tool, paste an image, or choose files. The queue shows each source size before any work begins.
Choose 2× or 4×
Check the exact output dimensions and the memory warning. Pick PNG, JPG or WebP before you run the queue.
Inspect, then save
Drag the comparison split and switch to 100% zoom. Download only when the invented detail looks right for this image.
Using the AI image upscaler
The tool is built around the decision you actually need to make: is the new detail useful, or merely convincing at a small preview size? Every control keeps that answer visible.
Add images and manage the queue
Drop JPG, PNG, WebP or AVIF files on the large target. You can also paste an image or use Choose images. Each file appears in the queue with its dimensions and byte size. Select a row to inspect it. Add images keeps the current queue, while Clear queue releases every source and result from the page.
Choose the scale and output
2× doubles each edge and creates four times as many pixels. 4× creates sixteen times as many. The selected image panel shows the exact result before processing. PNG preserves transparency. JPG and WebP reveal a quality slider because both formats trade some image information for a smaller file.
Run a batch and understand progress
Upscale runs every waiting item in order. The first use fetches a 4.9 MB model and prepares it in a worker. Tile progress then shows how much of the current image is complete. Cancel stops the active job and keeps the source queue intact.
Compare the real result
Drag the ↔ handle over the image to move the split. You can also focus it and use the arrow keys. Hold to see original removes the result while you hold it. Fit shows the whole picture. 100% maps one result pixel to one screen pixel, which is where false edges, waxy skin and broken lettering become clear. The plus and minus buttons cover the space between those views. Full screen gives the comparison more room.
Download only the version you checked
The selected image panel reports the encoded result size after processing. Download result saves that item in your chosen format. When at least two results are ready, Download all as ZIP appears below it. Source files, result pixels and previews are held in memory. They are not saved to your floi account.
What the model changes
Ordinary enlargement interpolates between known pixels. AI super-resolution also predicts the texture likely to sit between them. That can make hair, foliage and material edges look more natural. It can also invent a stroke in small text or a feature on a distant face.
This tool uses the compact Real-ESRGAN general 4× model. Its authors describe the small model as faster and lighter, with weaker denoising and deblurring than larger alternatives. The tradeoff suits an in-browser tool. It is not the right choice for forensic work or for a damaged photograph that needs manual restoration.
Why the 36 megapixel limit exists
A compressed file hides how much memory its pixels require. A 3000×3000 image at 4× would become 12,000×12,000. The final RGBA bitmap alone would occupy about 576 MB. Model tensors and the source need more memory beside it. The tool caps output at 36 megapixels and 12,000 pixels per edge, then explains the rejected size before starting.
If a source is too large, choose 2× or use the image resizer first. If you only need fewer bytes rather than more pixels, use the image compressor. Upscaling is the most expensive option, so it should answer a real size problem.
What it will not do
It will not recover evidence. The model predicts plausible detail. It does not reveal information that the source failed to capture.
It will not keep metadata. The browser decodes the file to pixels and writes a new one. EXIF, GPS and camera settings are not copied into the download.
It will not beat every desktop model. A large GPU application can offer several specialist models and process bigger files. This tool favours a private, inspectable workflow that opens without an install or account.
Frequently asked questions
Does this AI image upscaler upload my photos?
No. The image decoder, AI model and encoder run inside your browser. The page fetches a 4.9 MB model from models.floi.dev the first time you use it, but your image is never included in that request. The cached model can then run offline.
Can AI restore detail that is missing from an image?
No. An upscaler predicts texture that looks plausible from the pixels it can see. It cannot recover a face, licence plate, signature or small text that the source never recorded. Treat the result as an improved picture, not new evidence.
Does 4× mean the image becomes 4K?
No. It means four times the width and four times the height, which is sixteen times as many pixels. A 640×480 image becomes 2560×1920. A 960px-wide image becomes 3840px wide, which matches the width commonly called 4K.
Why does the tool stop some large images?
AI upscaling needs the source, model tensors and finished bitmap in memory at the same time. A 6000×4000 result alone needs about 96 MB as raw RGBA pixels. This tool stops at 36 megapixels and 12,000 pixels on either side so a large job fails clearly instead of crashing the tab.
Should I choose 2× or 4×?
Start with 2× when the source is already close to the size you need. It is faster and asks the model to invent less. Use 4× for a genuinely small source, then inspect hair, text, brickwork and repeated patterns at 100% before you keep it.
Which image format should I download?
PNG keeps transparency and adds no further compression loss, but it can be large. JPG is usually the practical choice for photographs. WebP often makes a smaller file at similar visible quality. The quality slider appears for JPG and WebP.
Why can local AI take longer than an online upscaler?
The work uses your own CPU rather than a remote GPU. The first run also downloads and prepares the model. In return, there is no image upload, account, credit counter or server queue. Later runs can reuse the cached model.
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