Tweaking a theme

Hy,

I downloaded this theme called MiniFolio from WPExplorer.com (https://www.wpexplorer.com/minifolio-wordpress-theme), and I like it how it looks but I would love to make some changes on it and I couldn’t find help from were I downloaded it.

What I would like to change is:
– the slider on the Home page to have customizable size so I could make it bigger (https://zolti.lehel.in/blog/);
– to add the possibility to comment on the Portfolio type of pages too, not only on the Blog pages (https://zolti.lehel.in/blog/?portfolio=element3);
– to add an unique picture to the About the Author section above the comments (https://zolti.lehel.in/blog/?p=128, down, just before the Comments section);
– I don’t know if there is a plugin out there to do this or can be implemented into the theme but I would love to be able to rate every photo, no matter where it is (except the photos from the slider on the Homepage).

I know that the pictures are too big and it does take a while to display them, but currently my blog is in development and, at the moment, I care more about its look then its content so that’s why I uploaded random pictures found on my computer.

I would appreciate any help possible,

Zolti