1.where the images are stored in database or response of attended questions with image (table name )
2.Where the images are stored in moodle file.
It is quite complex. The files table contains a pointer to where the files are stored. The files are physically stored with the name hashed, i.e. an incomprehensible list of apparently random letters and numbers e.g. 5b1a8f4657a5d4b2ca3ee04a986947aea7294c3e
This page may help explain further
https://docs.moodle.org/dev/File_API_internals#File_storage_on_disk