An image scanner turns a photo of a page into a clean, flat scan. Instead of a flatbed machine, it uses a picture you took with your phone or camera, finds the edges of the paper, straightens it and saves it as a PDF or image. This guide explains how it works and how to use a free image scanner online.
How an image scanner works
- You provide a photo. Take a new one or choose one you already have.
- The page edges are found. You drag four corner points onto the paper, or use automatic detection.
- The page is straightened. A tilted or angled photo is flattened into a rectangle, so the page looks as if it was scanned flat.
- You save it. Export one page as JPG or PNG, or combine many pages into a PDF.
Using the free WriteDroid Image Scanner
The WriteDroid Image Scanner does all of this in your browser, on your phone or computer.
- Open the image scanner.
- Press Choose images, or Take photo on a phone. Selecting several images at once works.
- Drag the dots to fit the page. Corner dots move one corner and edge dots move a whole side. Or press Auto detect.
- Press Apply and check the Preview tab. Use Re-crop to adjust.
- Save a PDF, or save a single page as JPG or PNG.
Automatic edge detection and AI
The scanner has a built in edge finder that works on your device. It can also use AI page detection, which is optional. When AI is on, each photo is sent to an AI service only so it can find the page edges, and it is not saved. You can switch it off with the checkbox, and you can always fix the corners by hand.
What you can scan
- Forms, applications and assignments
- Receipts, bills and invoices
- Notes, book pages and whiteboards
- ID cards, certificates and mark sheets
- Contracts and letters
Tips for a sharp scan
- Use bright, even light and avoid shadows from your hand or phone.
- Keep the camera parallel to the page.
- Photograph a white page on a dark surface for clear edges.
- Clean the camera lens. A smudge softens the whole picture.
- Do not zoom in digitally. Move closer instead.
PDF, JPG or PNG?
- PDF is best for documents with one or more pages, and for sending or printing.
- JPG is smaller and good for photos and quick sharing.
- PNG keeps sharp edges, which suits screenshots and text.
Free and no watermark
The scanner is free, needs no account and does not stamp a watermark on your pages. You can add your own watermark text, such as CONFIDENTIAL, in the PDF options if you want one.
Limits to know about
It does not read the words in your scan, so the PDF is not searchable, and it does not store your files online. If you need text recognition or cloud folders, a dedicated app is a better fit. For clean pages saved as a PDF, JPG or PNG, a browser scanner is quick and simple.
Next, read how to scan a document with your phone camera, how to use an image to PDF converter and how to scan on a PC.