You can easily use Lightbox2 on anchored images inserted by TinyMCE or FCKEditor, by using the "custom image trigger classes" feature.
Note that IMCE may also be used.
- Go to the Lightbox2 Automatic image handling settings page (admin/settings/lightbox2/automatic).
- In the Custom image trigger classes textarea, add a new class that will be used to trigger the Lightbox (e.g. "triggerclass") then click "Save Configuration". Note: This feature is not available when using Lightbox2 Lite.
- Choose the appropriate Lightbox2 image handler from the drop-down list, e.g. 'Lightbox', 'Lightbox grouped', 'Slideshow', etc.
- Go to the TinyMCE settings page (admin/settings/tinymce) and edit one of your created profiles.
- On Buttons and plugins settings: make sure the advanced image and image checkboxes are checked.
- On CSS settings, CSS classes: add the newly created class Lightbox2, using the = format. (i.e, trigger=triggerclass) then click "Update Profile".
- Create your content and click on the image button on the TinyMCE toolbar,.
- In the Insert/edit image window on the General tab, click on "browse" and insert a thumbnail image. You may also want to set an image description as it will be the caption for image.
- On the Appearance tab, click on the Class pull down menu and choose the Lightbox2 trigger class (i.e. "triggerclass"), then click "Insert".
- With the inserted image clicked, click the Insert/edit link on the TinyMCE toolbar.
- On the Insert/edit link window, browse for the bigger image and click on "Insert", continue creating / editing your content and save it.
- Create your content, and on the FCKEditor toolbar click the image button.
- In the Image Properties window, Image info tab, click "browse" and insert a thumbnail image. (You would also want to type in the Alternative text: as it will be the caption for image.)
- On the Advanced tab, in the Stylesheet Classes textfield type in the Lightbox2 trigger class (i.e. "triggerclass"), then click OK.
- With the inserted image clicked, click the Insert/Edit Link on the FCKEditor toolbar.
- In the Insert/edit link window, browse for the bigger image and click on "Insert", continue creating / editing your content and save it.
There is a patch for FCKeditor queue to allow configuration of the rel attribute on links, see http://dev.fckeditor.net/attachment/ticket/2627/fck-rel.patch
For more advanced integration of FCKEditor, IMCE and Lightbox2, check out this article: http://drupal.org/node/314566