change the read more starting position

Dear Sakin happy new year! i am creating a blog with the Simple Pro theme. and i have a few questions. First of all i would like to know if it is possible to change the starting position in a post when you click on a read more. i would like it to start at the beginning of the post. secondly; where can i change the size of the image shown in the light box? i use the plugin flickr gallery but the lightbox displays only a thumbnail. while flickr contains the larger image. in the plugin it is set to display largest image size fitting to the screen. my site is: website> PS the insert link does not work here in the post