Where is the html file located?

I wanted to customize my main page to do some image linking, meaning when u click on the image. U will be linked to another page or something. I know there are plugins to do image links, but I want to do it hands on. So where do I find the html script ? I need to customize the <a href="xxxxxxxx">.

thanks for replying, but i want to find the specific image link script.
let's say i've uploaded example.jpg, then where can i find the html script with the specific link that has <a href="example.jpg">. cant find it the template, album, and photos. Thanks"