When you press 'Reindex' button on the index page, DAlbum scans all subdirectories of  /photo/pictures for .JPG, .GIF and .PNG image files.

For every found image DAlbum creates a thumbnail in _thm subdirectory, and a resized version of the image in _res subdirectory.

For example /photo/pictures/2003/Birthday directory contains 2048x1536px img001.jpg:

DAlbum creates a 128x128 thumbnail (resolution is configured in config.php) of the image as _thm/thm_img001.jpg and 800x600 resized version as _res/res_img001.jpg:

In addition to that, a skeleton of album definition file .albumdef.ini is created in every directory. This file contains various information - album name, comments, access-control directives and titles of individual images.

Convenient web-interface is provided for editing .albumdef.ini files, but you can modify it with any text editor. Please note that after making changes with an external editor you need to reindex the album manually for your settings to apply. Changes made through web-interface apply immediately.

Example of .albumdef.ini:

[Album]
; Album title, date and comments.
Title=Baby Shower party
Date=Jun 2003
Comment=
CommentHTML=This was my <b>Baby Shower</b>party

; Title image specifies album image that will be shown as album thumbnail.
; First image is default if not specified
TitleImage=pic1.jpg

; Default=1 - show this album when DAlbum is started
Default=0

; Access control - comma-separated user list or 'valid-user' for "any user"
; Empty string or 'all' allows anonymous access
Access=valid-user

; --------------- Album files --------------------------
[pic1.jpg]
Title=This is picture1
Comment=This is plain-text comment
CommentHTML=

[pic2.jpg]
Title= This is picture2
Comment=
CommentHTML=<b>HTML</b> comments are <strike>cool</strike>

You can use multi-line parameters (useful for comments) by terminating the line with "\" character. For example:

CommentHTML=\
This was my <b>Baby Shower</b>party<BR>\
This is the second line!

After reindexing, a file /photo/.private/.album_index.dat is created. This file contains photo album structure and is used every time the album tree is displayed. When album folder is renamed or other big change occurs, reindex should be done again to update this directory structure file.

In addition to /photo/.private/.album_index.dat file, a special .album_hash.dat hidden file is created in every _thm directory. This file is used to detect possible changes made to album original images and regenate corresponging thumbnails.

Notes:

1. Files and directories starting with _ or with . are skipped by reindexing process.
2. Thumbnails and resized images are created only if they do not exist or if the size of original image has changed. There are three possible ways to regenerate already existing thumbnails:
   • To redo all thumbnails in all albums (for example when resolution or ImageMagick parameters were changed), reindex in "Extremely Slow" mode. This operation may easily take several hours.
   • To recreate thumbnails for individual albums, delete the corresponding thm_* and res_* files with an FTP browser and then reindex in 'Fast' mode.
   • To redo individual images there is a special 'Update' toolbar button which must be enabled in config.php by setting

     $g_bShowUpdateButton=true;

3. By default resized image size is set to 50000x600. In other words, no resized image can exceed 600 pixels in height but is practically unlimited in width. This was made on purpose to support panoramic images.
4. GIF and PNG files are not resized by default. If you need to display a map or screenshot in your album that should not be resized to preserve image quality - put it in GIF or PNG format. It is also possible to change this setting individually for each picture in .albumdef.ini file by adding Resize=1 or Resize=0 variable to the file section.