Images disappeared after installation transfer

I have transferred Elgg installation quite a number of times but have never experienced such an issue.

 

Recently, we decided to move our Elgg site from shared to VPS. The installation went well. But, all the images (Groups, profile, Tidypics, everything ...) disappeared.

Otherwise, the site works well.

 

Could anyone please suggest any reason for this and possible remedies ...!

 

*the data directory has 775 permission and new images can be uploaded. The previous images are found on the data directory.