Rotate and Flip an Image
Turn a photo by any angle, straighten a crooked horizon, or mirror it. Fixes sideways phone photos permanently, not just on your screen.
Quick turns
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Why Phone Photos Turn Sideways
Your phone does not physically rotate the pixels when you turn it. It writes the picture in one orientation and adds a tag saying "display this rotated 90 degrees". That tag is part of the EXIF metadata.
Modern apps read the tag and show the photo correctly. Older software, some upload forms, and a lot of printing services ignore it, so the same file looks right on your phone and sideways everywhere else.
This tool bakes the rotation into the pixels themselves, so the file is correct no matter what opens it. If you want to see the tag first, the EXIF viewer shows the Orientation field along with everything else in the file.
Straightening a Horizon
A tilted horizon is usually only one or two degrees out, and that is enough to make a photo feel wrong without anyone knowing why.
- Use the fine angle slider and the half degree buttons. Most corrections land between 0.5 and 3 degrees.
- Compare the horizon against the top edge of the preview box, which is perfectly level.
- Rotating by a non right angle leaves empty wedges in the corners. Either fill them with the corner colour, or crop them away afterwards.
- To crop them away, download the rotated file and run it through the image cropper.
Doing It in GIMP
| What you want | Where it is |
|---|---|
| Turn the whole image 90 degrees | Image > Transform > Rotate 90° clockwise |
| Mirror the whole image | Image > Transform > Flip Horizontally |
| Turn one layer by a free angle | Tools > Transform Tools > Rotate, or press Shift+R |
| Straighten by drawing along the horizon | Tools > Transform Tools > Measure, then Straighten in the tool options |
| Mirror only one layer | Tools > Transform Tools > Flip, or press Shift+F |
The Measure tool trick is the best kept secret here. Drag a line along something that should be level, then click Straighten in the tool options, and GIMP works out the angle for you. The straighten a horizon guide walks through it.
Common Questions
Why did my image get bigger after rotating?
Rotating a rectangle by an angle needs a larger canvas to hold the corners. Tick "Keep the original canvas size" if you would rather the corners were cut off than the canvas grow.
Does rotating lose quality?
90, 180 and 270 degrees are lossless, since pixels just move. Any other angle interpolates and softens the image very slightly.
Is mirroring the same as rotating 180 degrees?
No. Mirroring produces a reflection, rotating turns the picture upside down. Text stays readable when rotated, and becomes backwards when mirrored.
Can I rotate a whole folder?
The Script-Fu generator has a rotate recipe that runs over a whole folder in GIMP.