This is a sample script for cropping images in the Google Slides using Google Apps Script. In the current stage, in order to crop the images in Google Slides, it is required to use replace(blobSource, crop) Because, although there is the "cropProperties" of "UpdateImagePropertiesRequest" in Slides API, unfortunately, in the current stage, this cannot be still used. This has already been reported. Ref
About cropping using replace(blobSource, crop), I thought that how to use might be a bit difficult. So here, I would like to introduce a sample script for using replace(blobSource, crop).
