(setq sourceFolder "~/Vídeos/Cursos")
(setq reportResult "~/Reporte.md")
(setq myExtentionList '())

(dolist
(myItemVar (directory-files-recursively sourceFolder ""))
(add-to-list 'myExtentionList (file-name-extension myItemVar)))

(write-region "| " nil reportResult)

(setq myFilesList '())

(dolist (myExtVar myExtentionList)
(add-to-list 'myFilesList (directory-files-recursively sourceFolder myExtVar)))

(setq columnCount (length myFilesList))

(setq fieldCount 0)
(dolist (myColumn myFilesList)
(if (> (length myColumn) fieldCount)
(setq fieldCount (length myColumn))))

(setq field 0)
(while (< field 1)
(setq column 0)
(while (< column columnCount)
(write-region (concat (file-name-extension (nth field (nth column myFilesList))) " |") nil reportResult 'append)
(setq column (1+ column)))
(setq field (1+ field)))

;; | png | jpeg | jpg | gif |
;; |----------|-----------|----------|----------|

(write-region "\n|" nil reportResult 'append)

(dolist (myItemList myExtentionList)
(write-region "-----|" nil reportResult 'append))

(write-region "\n" nil reportResult 'append)

(setq field 0)
(while (< field fieldCount)
(setq column 0)
(while (< column columnCount)
(setq iterateItem (nth field (nth column myFilesList)))
(if (not (equal iterateItem nil))
(write-region (concat (concat (concat (concat "| " (file-name-nondirectory iterateItem)) " iterateItem) ") ") nil reportResult 'append)
(write-region "| " nil reportResult 'append))
(setq column (1+ column))
(if (equal column columnCount)
(write-region "|\n" nil reportResult 'append)))
(setq field (1+ field)))

(find-file reportResult)

;; | img0.png | img0.jpeg | img0.jpg | img0.gif |
;; | | img1.jpeg | img1.jpg | img1.gif |
;; | | img2.jpeg | img2.jpg | |
;; | | | img3.jpg | |
;;