def sf_fix_imgs(imgs, uri, exts = [])
      sf_check_img_ext(imgs.map do |img|
        img = img.to_s
        unless img =~ sf_regex(:protocol)
          img = sf_fix_protocol(img, sf_domain(uri))
        end
        img if img =~ sf_regex(:image)
      end.compact, exts)
    end
def sf_fix_imgs(imgs, uri, exts = [])
      sf_check_img_ext(imgs.map do |img|
        img = img.to_s
        unless img =~ sf_regex(:protocol)
          img = sf_fix_protocol(img, sf_domain(uri))
        end
        img if img =~ sf_regex(:image)
      end.compact, exts)
    end
Check and return only the valid image URIs.

 Example:
   >>  sf_fix_imgs(
         ['http://adtangerine.com/image.png', '/assets/image.jpg'],
         'http://adtangerine.com',
         :jpg
       )
   => ['http://adtangerine/assets/image.jpg']
 Arguments:
   imgs: (Array)
     - Image URIs got from the HTML doc.
   uri: (String)
     - Used as basis to the URIs that don't have any protocol/domain set.
   exts: (Symbol or Array)
     -  Allowed image extesntions.