(setq thumb-file (image-dired-get-thumbnail-image image-file))
;; If image is not already added, then add it.
(let ((cur-ov (overlays-in (point) (1+ (point)))))
(if cur-ov
(delete-overlay (car cur-ov))
(put-image thumb-file image-pos)
(setq thumb-file (image-dired-get-thumbnail-image image-file))
;; If image is not already added, then add it.
(let ((cur-ov (overlays-in (point) (1+ (point)))))
(if cur-ov
(delete-overlay (car cur-ov))
(put-image thumb-file image-pos)