Resize Images on Linux

To publish pictures in my gallery I have to resize them. Doing this picture per picture is annoying, I want to batch resize the images – the best solution would be a command line tool that accepts wildcards (*) so that many files (e.g. all in a specified folder) can be modified at once. With ImageMagick this is a very easy task under Linux: the command mogrify -resize "1200>" */*.JPG resizes all files with the ending .JPG in all subfolders to a width of 1200 pixels. The resize operation is only done if the original is larger than 1200 pixels (option >).

Autorotate Images on Linux

Cameras store information about the orientation of an image in the so-called exif. Many programs automatically rotate images when displaying them. However they do not store the image after the rotation which is necessary if you want to publish your pictures in a gallery. Under linux the tool jhead does this job for you.
The command jhead -autorot *.jpg will rotate all files ending with .jpg in the current folder if necessary (i.e. if the exif-data indicate that you should rotate the image).