not working with large image size

I have a problem.
I can’t post activity with file too large.
If I try with little size image it will works.
If I try with a large image (example JPG 2,4 MB – 3872 × 2592 px), the preview works fine and there is no error where confim the post, but the post not show in the list of activities.
Why??
With debug I found that the problem maybe is in the function “move_images” in file “class_bpfb_binder.php”.
Infact the script work fine until the

row image_resize($new_img, $thumb_w, $thumb_h, false, ‘bpfbt’);

after this row, the script don’t go….

someone can help me??

thank you.

http://wordpress.org/extend/plugins/buddypress-activity-plus/