Python snippet to generate captions based on EXIF data

mark.py

from PIL import Image, ImageDraw, ImageFont
import os
from PIL.ExifTags import TAGS
# get an image

fnt = ImageFont.truetype('Ubuntu-R.ttf', 30)

for name in os.listdir('images'):
    print name
    img = Image.open('images/' + name)
    exif = {
    TAGS[k]: v
    for k, v in img._getexif().items()
    if k in TAGS
    }
    del exif['MakerNote']
    info_string = ''
    info_string += 'A = f/' + str(float(exif['FNumber'][0])/exif['FNumber'][1])
    info_string += ', SS = 1/' + str((exif['ExposureTime'][1])/exif['ExposureTime'][0]) + 's'
    info_string += ', ISO = ' + str(exif['ISOSpeedRatings'])
    print info_string
    base = img.resize((800, 600), Image.ANTIALIAS).convert('RGBA')
    txt = Image.new('RGBA', base.size, (255,255,255,0))

    d = ImageDraw.Draw(txt)


    d.rectangle((340,570,800,600), fill=(0,0,0, 200))
    d.text((350,570), info_string, font=fnt, fill=(255,255,255,255))

    out = Image.alpha_composite(base, txt)

    out.save('output/' + name)