Error when trying to upload images

[T-bird]

Had a major crash of my website due to corrupt databse files so while trying to sort that out I upgraded to 1.4.9.0. I managed to restore most of the database from the back up I made before the crash, however when I try to load missing images Prestashop keeps throwing errors. When I check the error log I get this:

 

PHP Warning: imagejpeg() [<a href='function.imagejpeg'>function.imagejpeg</a>]: Unable to open '/home/thunderb/public_html/img/p/902-2486.jpg' for writing: Permission denied in /home/thunderb/public_html/images.inc.php on line 346

 

I've checked "/images.inc.php" but I don't know what the issue is. Permissions on img folder is set at 755, however if I set permissions to 777 it works for some images. I'd rather not have them at 777 though and don't understand why 755 doesn't work anymore.

 

Anyone know what the problem is?