Is Codeigniter good for my website?

lol... If I were a developer. Since I'm not can anyone tell me

1. whats best for the forum part for my site?
2. whats best for the picture database part for my site?

Since you are not a developer, you should write down your requirements as SMART as possible and discuss them with the person are team that is going to build your website.
A developer (or development team) should decide which technological solution fits best to meet your requirements. That shouldn't be your concern.
If you do plan to build a website yourself, you will have to learn skills to do that. CodeIgniter is not a tool that will build an application for you, without you needing to know about php, mysql, css and javascript.