Copyright - Can I use the images? Model vs Photographer

I am a paid model, my work comes from both agencies and portfolio websites such as Photographers pay me to take photos of me and my question is am I allowed to use these images on a personal portfolio website that I own? Must I ask the photographer permission to use the photos or do I have some kind of ownership as photographers paid me to take them in the first place or can I simply credit the photographer on my website? (and also keep intact any copyright notices they have put onto images they have taken of me).
In the future should I write up an agreement with photographers stating that I would like to use the images created during a shoot on my website?
Asked Jun 02, 2015

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