When I scan photos on my printer, sometimes it is a dumb printer and does not take out the background, especially when there is a lot of white. How would I do this on my example photo other than selecting it with the selection tool? autocrop and zealous crop does nothing.
Select the white area using color selection, invert selection, then crop to selection. If not enough of the border is selected, increase the selection threshold.
You don't have to worry about white areas within the image, such as the fountain, because the crop is rectangular. However images with white across an entire edge, such as blown out skies, may have to be cropped manually.
You can speed up the selection operations by performing a rough initial crop to decrease the image area the software has to analyze.