How can I change the metadata for several images at the same time (batch edit)? For example, comments and titles.
There are two good tools to edit meta-data of image-files:
exiftool and exiv2
You will find exif here: official site
It also has a graphical frontend: frontend for exif
You can try installing gThumb Image Viewer, by typing on the Terminal:
sudo add-apt-repository ppa:webupd8team/gthumb sudo apt-get update sudo apt-get install gthumb