Hi Peterpix,

I have notified "serge D" :-)

BTW this is not a local computer cache issue, as I have just tried on a different computer on which I had not viewed this album before and the result is the same.

In relation to the first affected photo I have defined the man's face as the centre of interest.

In the second one (the woman with head resting on hand) I had defined a close crop around her whole figure from head to toes.

sorry for the delay, many things...

just to confirm, you changed your settings not to crop right now, except big thumb

Please note that there are two things which happens in masonry mode:
* crop is done to resize the image to rough size which is then used to arrange the thumbs - at that stage PWG should take COI point into consideration
* then system is trying to auto-fit the images to cover viewport. At this stage browser viewport size is used and no thumb regeneration would be triggered. As result COI is no longer in play as javascript used has no knowledge of that information nor is there any metadata in thumbnail object which is accessed by php beside some cryptic reference like

[coi] => jjvz

So I do not have much to adjust my logic on
Any suggestions are welcomed

the COI must be interpreted like that : it's 4 fractions of z (26)

jjvz =>
10/26
10/26
22/26
26/26

use char_to_fraction function convert each component

$tpl_var['coi'] = array(
    'l'=> char_to_fraction($row['coi'][0]),
    't'=> char_to_fraction($row['coi'][1]),
    'r'=> char_to_fraction($row['coi'][2]),
    'b'=> char_to_fraction($row['coi'][3]),
  );

each component is the position of the edges of the COI rectangle relative to the image size

jjvz =>
COI left is at 0.384 of the image left
COI top is at 0.384 of the image top
COI right is at 0.846 of the image left
COI bottom is at the image top