Problem with condensation or leak (photos included) ?

Hi Guys,

I was wondering if anyone here can give me some advice as to what could be causing the marks on 2 of the walls in my house. These wall are facing towards the outside of the house (external facing walls).

The house was painted around 2 years ago and I found these today, they might have been there for some time.

Please let me know if you need more information.

Thanks.

Attached Thumbnails

     

Problem with condensation or leak (photos included) ?