Variable: image-dired-thumbnail-storage

image-dired-thumbnail-storage is a customizable variable defined in image-dired.el.gz.

Value

image-dired

Documentation

How image-dired stores thumbnail files.

There are three ways that Image-Dired can store and generate thumbnails:

 1. According to the Thumbnail Managing Standard, which allows
    sharing of thumbnails across different programs. Thumbnails
    will be stored in "$XDG_CACHE_HOME/thumbnails/"

    Set this user option to one of the following symbols:

    - standard means use thumbnails sized 128x128.
    - standard-large means use thumbnails sized 256x256.
    - standard-x-large means use thumbnails sized 512x512.
    - standard-xx-large means use thumbnails sized 1024x1024.

 2. In the Image-Dired specific directory, as indicated by
    image-dired-dir(var)/image-dired-dir(fun).

    Set this user option to image-dired (use-image-dired-dir
    also works, for backward-compatibility reasons).

 3. In a subdirectory ".image-dired" in the same directory
    as the image files.

    Set this user option to per-directory.

To control the default size of thumbnails for alternatives (2) and (3) above, customize the value of image-dired-thumb-size(var)/image-dired-thumb-size(fun).

With Thumbnail Managing Standard, save thumbnails in the PNG format, as mandated by that standard; otherwise save them as JPEG.

For more information on the Thumbnail Managing Standard, see: https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html

This variable was added, or its default value changed, in Emacs 29.1.

Probably introduced at or before Emacs version 26.1.

Source Code

;; Defined in /usr/src/emacs/lisp/image/image-dired.el.gz
(defcustom image-dired-thumbnail-storage 'image-dired
  "How `image-dired' stores thumbnail files.
There are three ways that Image-Dired can store and generate
thumbnails:

 1. According to the Thumbnail Managing Standard, which allows
    sharing of thumbnails across different programs.  Thumbnails
    will be stored in \"$XDG_CACHE_HOME/thumbnails/\"

    Set this user option to one of the following symbols:

    - `standard' means use thumbnails sized 128x128.
    - `standard-large' means use thumbnails sized 256x256.
    - `standard-x-large' means use thumbnails sized 512x512.
    - `standard-xx-large' means use thumbnails sized 1024x1024.

 2. In the Image-Dired specific directory, as indicated by
    `image-dired-dir'.

    Set this user option to `image-dired' (`use-image-dired-dir'
    also works, for backward-compatibility reasons).

 3. In a subdirectory \".image-dired\" in the same directory
    as the image files.

    Set this user option to `per-directory'.

To control the default size of thumbnails for alternatives (2)
and (3) above, customize the value of `image-dired-thumb-size'.

With Thumbnail Managing Standard, save thumbnails in the PNG
format, as mandated by that standard; otherwise save them as JPEG.

For more information on the Thumbnail Managing Standard, see:
https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html"
  :type '(choice :tag "How to store thumbnail files"
                 (const :tag "Use image-dired-dir" image-dired)
                 (const :tag "Thumbnail Managing Standard (normal 128x128)"
                        standard)
                 (const :tag "Thumbnail Managing Standard (large 256x256)"
                        standard-large)
                 (const :tag "Thumbnail Managing Standard (larger 512x512)"
                        standard-x-large)
                 (const :tag "Thumbnail Managing Standard (extra large 1024x1024)"
                        standard-xx-large)
                 (const :tag "Per-directory" per-directory))
  :version "29.1")