How to rotate an image using GIMP


#1

How do I rotate an image 3° using GIMP. The View -> Flip and Rotate rotates the view of the image, not the image itself. The image is a .tiff file produced by a scanner. The image is tilted about 3°. How do I get rid of this tilt?


#2

Tools > Transform > Rotate

Goes in 0.1 degree increments. If hardware is fast enough, will show approximate rotation in near real-time. When rotation is correct, click on Rotate button to execute changes on actual image. Then Export As, if you want to resave as .tiff. There will be a number of choices for compression method and resolution.

Another useful tool for scans, once rotated is to select and cut the rectangular area you want, and paste as a new image. This can cut away extraneous stuff around the edges.


#3

I tried the rotation tool. When I export it as a png image and display it in Chrome, the original un-rotated image appears.


#4

I'm no GIMP expert--but am not seeing that happen here. A rotated, exported png displays correctly in any of several other viewers, including Chromium (which is as close to Chrome as I can get). And that makes sense, because there is no place to even store "previous rotation" information in the png file structure.

One "gotcha" that tripped me up a few times was that the Tools > Transform > Rotate
dialog requires 1) that you enter the angle AND 2) that you click "Rotate" button to make the changes permanent. Otherwise, it just shows a temporary view of the image.