Question 1

Which angles can I rotate by?

Accepted Answer

Ninety, 180 or 270 degrees clockwise, chosen with the Rotation option, which defaults to 90. Arbitrary angles are not offered, and there is no mirror or flip here. A 90 or 270 degree turn swaps the width and height of the image; 180 keeps them. The pixels are moved one by one, so nothing is resampled or blurred.

Question 2

Is rotating lossless?

Accepted Answer

The rotation itself is exact, but the file is re-encoded afterwards. A lossless format such as PNG comes back with every pixel value unchanged. A lossy one is encoded again at the Quality option, default 80, so a JPG loses a little each time you run it. A GIF goes back through the 256-colour quantiser and returns as a single opaque frame, so transparency and any later frames are gone. This is not a lossless JPEG transform of the kind jpegtran performs.

Question 3

Will this fix a photo that only looks sideways in some apps?

Accepted Answer

It rotates the real pixels, which is a different fix. The re-encoded file carries no metadata at all, including no EXIF orientation tag, so every viewer will show it the same way. If an app was already auto-rotating your photo from that tag, check the result before deleting the original, since you might end up a quarter turn out.

Question 4

Does it upload anything?

Accepted Answer

No. Decoding, the pixel rotation and encoding all happen in a Web Worker in this tab, using the jSquash WebAssembly codecs. Nothing is uploaded and no account is involved. After the first visit the page works with your network turned off.

Question 5

What is the rotated file called?

Accepted Answer

Your name with the angle appended, such as scan-rot90.jpg, scan-rot180.jpg or scan-rot270.jpg. The format stays the same as the input apart from HEIC, and the extension is re-derived from it, so PHOTO.JPG comes back as PHOTO-rot90.jpg. Drop as many files as you like and each is rotated by the same angle and returned separately.

Question 6

Which formats does it read?

Accepted Answer

Every format Convert image reads, decided from the file extension. Anything else stops with a message naming your file and the formats that are readable. Transparency survives the rotation wherever the format carries an alpha channel, since alpha moves with each pixel along with its colour. A HEIC is turned and handed back as a JPG, because nothing here writes HEIC.

Tool	Runs on the CLI	Live as you type
Rotate image	Yes	No
Convert image	Yes	No
Compress image	Yes	No
Resize image	Yes	No
Crop image	Yes	No
Social preset resizer	Yes	No
ID / passport crop presets	Yes	No

Rotate image

Questions