default folder for rich media content of multiline text box

hi friends

i am using sp 2013 i have one list which contains multiline rich text box

if i am trying to insert image using insert button in ribbon it is prompting like below image

here my problem  is i need to set default destination Library name for saving this data. it should not show all document library names.

how can i do this

i can use only JavaScript or OOB functionality for this