I want to crop the white space in 300 pictures
Is there any software out there that does it?
There are enough programs, even free, which do what you want. Usually, these are picture managers which allow you to select the files/directories to process and what processing/conversion to do for them.
For example the procedure for the XnView (freeware) is as following:
Tools > Batch Processing...
Batch Processingwindow (the 'General' tab) set the destination directory (if you don't want to have your files overwritten) and the output format if you want to change it.
Transformationstab) select from the List of Available Transformations the
Auto Cropfeature and click
Addto add it to the list of the active transformations on the left. On the
Parameterspanel at bottom you will choose your desired color (white). Alternatively, if your images must be cropped at exactly same size and offset there is another option (transformation) which will work, perhaps, better.
Gobutton and check at the end your destination folder if everything went ok.
The entire process is much simpler than it sounds.
Irfanview. Press B to go to Batch conversion, add your images, click "advanced" and tick "Auto crop borders". Works a treat.