prepared to rewrote image/big_images/thumbnail part
changed thumbnail_size to min_image_size
moved normalize from rss_parser to image_helper
cleaned finding images segment
corrected finding images part from transcoded
updated find_biggest_image
removed unnecessary index number in find_biggest_image
finished center cropping and resizing
renewed constants
updated constant names
updated some constant varaible names
updated constant var names
updated constant var names
finished scale_image, the untested, primitive version
fixed a few typos
fixed a few typos
removed import random
finished simple tested scale_image
added some docs to scale_image
added constants for 3 types of image sizes