The current size is 295×220 for small sized images. The file framework.php in framework directory has the code which sets the image sizes. Look for functions get_easy_image_name_map() and get_image_sizes() after line number 120. You can change the image sizes here to suit your need and then use either
http://wordpress.org/plugins/force-regenerate-thumbnails/
or the
http://wordpress.org/plugins/regenerate-thumbnails/
to regenerate the thumbnails. Hope this works for you.