Inserting a string extent with a glyph in a buffer
When I do the following in 21.2 Demeter,
(setq mystr " ")
" "
(setq myext (make-extent 1 1 mystr))
#<extent [1, 1) 0x873a124 in string " ">
(set-extent-property myext 'duplicable t)
t
(set-extent-begin-glyph myext (make-glyph (vector 'jpeg :data jpegdata)))
#<glyph (buffer) #<image-specifier global=(((x) . [jpeg :data "ÿØÿà