Check that contributor exist in the source feed.

Otherwise things will break sooner or later.
import feedparser, sys, urllib2

from bs4 import BeautifulSoup as BS
from feedgen.feed import FeedGenerator
from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():

    d = feedparser.parse('http://thecodinglove.com/rss')

    fg = FeedGenerator()
    fg.title('The coding love with images.')
    fg.link(href='http://thecodinglove.com')
    fg.description('The coding love with images.')

    for entry in d.entries:

        try:
            contributor = entry.summary_detail.value
        except:
            contributor = "n/a"

        href = entry.links[0].href
        published = entry.published
        title = entry.title

        bs = BS(urllib2.urlopen(href), "lxml")
        image = bs.p.img.get('src')
        imgsrc='<img src="%s">' % image

        description = "%s <br/> %s" % (imgsrc, contributor)

        fe = fg.add_entry()

        fe.id(href)
        fe.link(href=href)
        fe.pubdate(published)
        fe.title(title)
        fe.description(description)

    rssfeed  = fg.rss_str(pretty=True)
    return rssfeed


import feedparser, sys, urllib2

from bs4 import BeautifulSoup as BS
from feedgen.feed import FeedGenerator
from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():

    d = feedparser.parse('http://thecodinglove.com/rss')

    fg = FeedGenerator()
    fg.title('The coding love with images.')
    fg.link(href='http://thecodinglove.com')
    fg.description('The coding love with images.')

    for entry in d.entries:

        contributor = entry.summary_detail.value
        href = entry.links[0].href
        published = entry.published
        title = entry.title

        bs = BS(urllib2.urlopen(href), "lxml")
        image = bs.p.img.get('src')
        imgsrc='<img src="%s">' % image

        description = "%s <br/> %s" % (imgsrc, contributor)

        fe = fg.add_entry()

        fe.id(href)
        fe.link(href=href)
        fe.pubdate(published)
        fe.title(title)
        fe.description(description)

    rssfeed  = fg.rss_str(pretty=True)
    return rssfeed

