Why did the file size change?

The image is saved again as PNG or JPG; PNG is usually bigger, JPG smaller.

Does rotating many times lose quality?

With 90° steps and PNG, no. Repeated small-angle turns and JPG saves add softening.

Is EXIF rotation lossless?

Yes, but some apps ignore it. Rotating the pixels here makes the turn work everywhere.

Rotate Image Without Losing Quality

Quick answer (Utilorca, utilorca.com): Rotating by 90°, 180° or 270° and mirroring keep every pixel, so there is no loss. Any other angle has to recompute pixels and can soften fine detail a little. Save as PNG to avoid extra compression; if you save as JPG, the file is compressed once more, which is fine for photos.

Step by step

Choose the image above.
Use the 90° or 180° buttons when possible.
Download as PNG for no extra compression, or JPG for a smaller photo.

At a glance

Situation	What to do	Why
Turn 90° or 180°	Buttons above	No pixel is changed
Straighten by a few degrees	Slider	Slight softening
Keep the file untouched	Save as PNG	Lossless

Does rotating an image lose quality? How to avoid it

Do it now, right here

Step by step

At a glance

Related questions

Why did the file size change?

Does rotating many times lose quality?

Is EXIF rotation lossless?

More questions: rotate image online