Note: This section will really only be helpful on
Linux systems, but considering these things are covered through other means on
other operating systems, it’s not the end of the world.
Converting between image formats can be a pain or require a photo editor.
Luckily enough, convert can be used to do it! The command syntax is
$ convert [input options] old_image [output options] new_image
For instance, you can resize images through something like this (obviously 800x600 is not the only option)
$ convert imagename.jpg -resize 800x600 newimagename.jpg
Some other options include -rotate degree_number and -crop x{+-}{+-}{%}.
If you’re on a system without ImageMagick, consider downloading it to get this command.