There is a target folder bug in the sidebar image uploader used across iWiccle 1.20 caused by the new AJAX PHP wrapper class. The module identifier is not correctly passed to the upload script, leading the image to be loaded to the default module's upload folder, because a default module is now established before the AJAX setup gets to handling it the way it needs to..

While the image in the new post is found because the /site/ path is inserted to your post's text area by the image uploader's Add button, if you return to edit a post, the system looks for it in the actual module's upload folder, resulting in a broken image.

If you want to fix this yourself, you can open up /core/class_ajax.php at line #49 and insert the following lines:

    if (!empty($_GET['module'])) $_SESSION['module']['module_ident'] = $_GET['module'];
    if (empty($_GET['module'])) $_GET['module'] = $_SESSION['module']['module_ident'];
    if (!empty($_POST['module'])) $_SESSION['module']['module_ident'] = $_POST['module'];

This would be right above this line:

    require_once(PATH_CORE."config_misc.php");

Otherwise, you can download this patch file that corrects the issue. This will be rolled into the next minor patch release, coming up shortly.