(see https://wiki.termux.com/wiki/Internal_and_external_storage)
termux-setup-storage
pkg install bc exiftool imagemagick termux-file-editor
termux-file-editor
allows one to share single files to termux, which will result in the file being copied in ~/download
folder and then have its full path passed to ~bin/termux-file-editor
, which I then use to interactively add a title (in the XMP metadata) and optionally recompress the jpg.