As I said, this is because /class/textsanitizer/image/image.js is missing in the header. Probably it is present when you are logged in.
The image scaling system varies with the img tag.
If you specify [img width=, then the width is enforced by
onload="JavaScript:if(this.width>300)this.width=300"
If you specify a plain [img] tag, then the max_width of the configuration file is enforced:
onload="javascript:imageResize(this, 300)"
The first resizing uses plain JavaScript and works always, but the second calls the imageResize() function and that must have image.js loaded. If that one is not there as I see when unlogged, then nothing happens, but in your browsers error console you will find some messages as Quote:
Error: imageResize is not defined
and Quote:
Error: CaricaFoto is not defined
Due to the missing script, the popup with the real size image is not shown when clicking the resized image.
The loading for the script is done by:
if (!empty($config['clickable']) && !empty($config['max_width']) && !empty($GLOBALS['xoTheme'])) {
if (!$jsLoaded) {
$jsLoaded = true;
$GLOBALS['xoTheme']->addScript('/class/textsanitizer/image/image.js', array(
'type' => 'text/javascript'));
}
I suspect something wrong with the xoTheme, while the other variables are in place, but I have no further clues.
Quick and dirty repair could be to insert the image.js in the header of your theme.html