How to flip, rotate or straighten an image

Flip a photo in four steps

1. 1

   Open the photo

   Choose File› then Open… and select your photo, or open the tram sample from this page.

2. 2

   Choose Image › Transform › Flip Canvas Horizontal

   Open Image› then Transform and choose Flip Canvas Horizontal. It applies immediately, with no dialog. The left and right sides exchange places; the photo keeps its width and height.

   

3. 3

   Check the mirrored picture

   In the sample, the tram now faces the opposite way. Writing and signs are mirrored too, so a flip is unsuitable when they need to remain readable. To go back to the original, choose Edit› then Undo.

   

4. 4

   Export the finished photo

   If you undid the flip, choose Edit› then Redo to restore it. Choose File› then Export› then JPEG…, type tram-flipped.jpg in File name and click Export. Export writes a new file.

   File› then Save writes the result back in the opened file’s format. The first Save of a JPEG opens Save Image. For a layered document, File› then Save As› then Lil Cactus Project… keeps the layers editable. After Save As, File› then Save updates that project.

   

Rotate a sideways or upside-down image

Choose one of these from Image› then Transform:

A 90° turn exchanges width and height: the 1536 × 1024 px sample becomes 1024 × 1536 px. Unlike a vertical flip, a 180° turn does not mirror the picture.

Straighten a tilted horizon

Use a distant horizon or a building edge that should be level. A sloping road or roof may really slope, so it is a poor guide. To practice, download the tilted-coast sample and open it with File› then Open…

1. Right-click the crop tools’ button in the left toolbar and choose Crop.
2. Set Ratio to Free, then click Straighten on the options bar, the strip below the menus.
3. Drag along the line where the sea meets the sky, from near the left edge to near the right edge. In the sample it slopes down to the right. Follow that distant horizon, not the diagonal shoreline in the foreground.
4. Release the pointer. The picture rotates and a crop frame appears inside the empty corners. Click Apply crop to finish.

Straightening removes some of the edges to fill a rectangular frame. Leave room around the subject when taking a photo that may need this correction.

Flip or rotate one layer

Select the layer in the Layers panel. For a photo layer made of pixels, Edit› then Transform› then Flip Horizontal or Flip Vertical mirrors that layer within the existing canvas. Other layers stay in place.

For an angle you choose, use Edit› then Transform› then Rotate, type the angle into Angle on the options bar and click the check mark to apply. The canvas does not expand, so a rotated layer may extend beyond its edges.

Fix common problems

Only one part of the picture moved

You used a command under Edit› then Transform. Undo, then use Image› then Transform for the whole document.

The image looks upside down instead of mirrored left to right

Undo and choose Flip Canvas Horizontal. Flip Canvas Vertical mirrors top to bottom, while Rotate 180° turns the photo through a half circle.

The horizon is still tilted

Choose Edit› then Undo twice (once for the crop, once for the rotation), then draw the reference along the distant horizon again. Starting and ending on different waves or on the shoreline gives the wrong angle.

I only want to turn my view while drawing

The Rotate View tool changes the working view. Use the Image menu commands when the exported image needs to turn.

What to do next

• Crop to a ratio or an exact composition after straightening.
• Resize the photo when its orientation is right.
• Correct leaning buildings when rotation alone does not fix the geometry.

Coming from another editor

Photoshop

Image › Image Rotation contains the whole-image rotation and Flip Canvas commands. In Lil Cactus these are under Image › Transform.

Flipping and rotating images: questions and answers