Can't upload .jpg files on PHP 5.3

I was running Dolphin V6.1.4 on a shared server with PHP 5.2 and asked my service provider to move it to a dedicated server. Now the users can't load .jpg files (.png and .gif files load fine). The file where the error occurs is uploadSharePhoto.php. The service provider says the new dedicated service is running PHP 5.3 which is in certain areas incompatible with D V6.1.4 Is downgrading back to PHP 5.2 the easiest solution? I am planning to upgrade Dolphin in the future but this will take a few months and I need a solution in the short term. Is there a code fix to the problem – or is installing PHP 5.2 the only solution for the time being? Thank you in advance Christine