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Letters Steganography Online: Hide Text in Images
Steganography online: hide a secret message inside an image, or decode the hidden text from an image you received. The image looks completely normal, and everything runs in your browser — no upload, no software, no sign-up.
About Steganography
Confileo's Steganography tool conceals a secret message invisibly inside an image. It works in any browser, free to start and without signup, and a file sent to our server is deleted automatically after processing.
Sometimes you want to send a message without anyone even knowing a message exists. Unlike encryption, which hides the content but not the fact that something is hidden, steganography conceals the message inside an ordinary-looking image.
Confileo's Steganography tool hides your secret text invisibly inside a cover image that looks completely normal; the recipient extracts it with the same tool. The process runs privately in your session and the file is deleted afterwards.
The technique is called least-significant-bit encoding. Every pixel in an image stores its colour as numbers, and changing the very last bit of each number shifts that colour by an amount no eye can register — but across thousands of pixels those spare bits add up to enough room for a message. The picture looks identical because, measured in colour, it very nearly is.
That is also why the output must stay PNG. PNG is lossless: every pixel comes back exactly as it was written. JPG re-computes pixel values to save space, and that recomputation destroys the hidden bits. If you save the result as JPG, re-upload it to a service that converts images, or send it through an app that compresses photos, the message is gone — the picture survives and the payload does not.
Capacity scales with pixel count, so a larger image holds a longer message. Photographs with detail and texture hide data better than flat graphics, logos or screenshots with large blocks of a single colour, where a changed bit has fewer neighbours to disappear among.
Treat this as concealment, not security. Anyone who suspects a message and runs the same tool can read it — there is no key. If the content genuinely needs protecting, encrypt it first and hide the encrypted text, so that finding it is not the same as reading it.
Quick facts
- Price
- 3 credits per file (free every month: 50 credits as a guest, 300 with a free account)
- Signup
- Not required
- Max file size
- Up to 100 MB per file
- Your files
- Deleted automatically after processing
- Works on
- Any browser — desktop, tablet, mobile
- Watermark
- None on your output
How to use Steganography
- Upload a cover image.
- Type the secret message to hide.
- Download an image that looks completely normal.
Why use Confileo
- ✓Try it free — 50 credits a month with no account and 300 a month with a free one; no watermarks and no credit card.
- ✓No signup or account required — start using it instantly.
- ✓Your files are processed securely and deleted automatically for full privacy.
- ✓Works in any browser on desktop, tablet and mobile — nothing to install.
- ✓Fast processing built to handle real, everyday document workloads.
Steganography — Frequently asked questions
Can anyone see the hidden message?
No. The image looks identical; only someone who knows to extract it can read the message.
Is the process private?
Yes. The hiding happens in your session and the file is deleted afterward.
How do I hide a text message inside an image?
Upload a cover image, type your secret message, and download an image that looks completely ordinary but carries the text inside.
How does the other person extract the message?
They upload the image in the same tool to extract the hidden message inside it.
Does the image change noticeably?
No. The image looks identical to the naked eye, and no one notices a message is inside.
What is the difference between hiding and encryption?
Encryption makes a message unreadable but its existence is visible; hiding conceals that a message exists at all inside an ordinary image.
Why must I keep the result as PNG?
PNG is lossless, so every pixel returns exactly as written. JPG recalculates pixel values to save space and destroys the hidden bits — save as JPG and the picture survives but the message does not.
Will the message survive if I send the image on WhatsApp or Instagram?
Usually not. Those apps recompress photos on upload, which rewrites the pixels the message lives in. Send the PNG as a file or document attachment rather than as a photo.
How long a message can I hide?
Capacity scales with pixel count, so a larger image holds more. Detailed photographs work better than flat graphics or logos, where an altered bit has fewer neighbours to blend into.
Can anyone tell that an image contains a hidden message?
Not by looking at it. But anyone who suspects it and runs the same tool can read it — there is no key. Treat it as concealment, not encryption.
Does hiding a message change how the image looks?
No visible change. Only the last bit of each colour value shifts, an amount far below what the eye can register.
Is this tool really free?
You can try it free: 50 credits without an account and 300 with a free account, renewed on the 1st of every month. Every tool uses credits — file tools 3 per file and the heavy ones 12. No watermark, no credit card. Beyond the monthly credits, Pro gives open use with no credits to count, or you can buy a credit pack.
Do I need to create an account?
No. You can use the tool straight away without signing up or logging in.
Are my files safe and private?
Yes. A file sent to our servers travels over an encrypted HTTPS connection and is deleted automatically after processing; tools that work in your browser never upload it. We don't open, read or sell your files.
Does it work on my phone?
Yes. The tool runs in any modern browser, so it works the same on desktop, tablet and mobile with nothing to install.