This script take pictures from directory and post it to tumblr blog and then delete it. Tumblr API v2! This example for oath file upload.

auth.py

import urlparse
import oauth2 as oauth

consumer_key = ''
consumer_secret = ''

request_token_url = 'http://www.tumblr.com/oauth/request_token'
access_token_url = 'http://www.tumblr.com/oauth/access_token'
authorize_url = 'http://www.tumblr.com/oauth/authorize'

consumer = oauth.Consumer(consumer_key, consumer_secret)
client = oauth.Client(consumer)

# Step 1: Get a request token. This is a temporary token that is used for 
# having the user authorize an access token and to sign the request to obtain 
# said access token.

resp, content = client.request(request_token_url, "GET")
if resp['status'] != '200':
    raise Exception("Invalid response %s." % resp['status'])

request_token = dict(urlparse.parse_qsl(content))

print "Request Token:"
print "    - oauth_token        = %s" % request_token['oauth_token']
print "    - oauth_token_secret = %s" % request_token['oauth_token_secret']
print 

# Step 2: Redirect to the provider. Since this is a CLI script we do not 
# redirect. In a web application you would redirect the user to the URL
# below.

print "Go to the following link in your browser:"
print "%s?oauth_token=%s" % (authorize_url, request_token['oauth_token'])
print 

# After the user has granted access to you, the consumer, the provider will
# redirect you to whatever URL you have told them to redirect to. You can 
# usually define this in the oauth_callback argument as well.
accepted = 'n'
while accepted.lower() == 'n':
    accepted = raw_input('Have you authorized me? (y/n) ')
oauth_verifier = raw_input('What is the PIN? ')

# Step 3: Once the consumer has redirected the user back to the oauth_callback
# URL you can request the access token the user has approved. You use the 
# request token to sign this request. After this is done you throw away the
# request token and use the access token returned. You should store this 
# access token somewhere safe, like a database, for future use.
token = oauth.Token(request_token['oauth_token'],
    request_token['oauth_token_secret'])
token.set_verifier(oauth_verifier)
client = oauth.Client(consumer, token)

resp, content = client.request(access_token_url, "POST")
access_token = dict(urlparse.parse_qsl(content))

print "Access Token:"
print "    - oauth_token        = %s" % access_token['oauth_token']
print "    - oauth_token_secret = %s" % access_token['oauth_token_secret']
print
print "You may now access protected resources using the access tokens above." 
print

photo2tumblr.py

import glob
import json
import os
import  time
import urllib2
import urlparse
import oauth2
from poster.encode import multipart_encode
from poster.streaminghttp import register_openers

class APIError(StandardError):
    def __init__(self, msg, response=None):
        StandardError.__init__(self, msg)

class TumblrAPIv2:
    def __init__(self, consumer_key, consumer_secret, oauth_token, oauth_token_secret):
        self.consumer = oauth2.Consumer(consumer_key, consumer_secret)
        self.token = oauth2.Token(oauth_token, oauth_token_secret)
        self.url = "http://api.tumblr.com"

    def parse_response(self, result):
        content = json.loads(result)
        if 400 <= int(content["meta"]["status"]) <= 600:
            raise APIError(content["meta"]["msg"], result)
        return content["response"]

    def createPhotoPost(self, id, post):
        url = self.url + "/v2/blog/%s/post" %id

        img_file = post['data']
        del(post['data'])
        req = oauth2.Request.from_consumer_and_token(self.consumer,
                                                 token=self.token,
                                                 http_method="POST",
                                                 http_url=url,
                                                 parameters=post)
        req.sign_request(oauth2.SignatureMethod_HMAC_SHA1(), self.consumer, self.token)
        compiled_postdata = req.to_postdata()
        all_upload_params = urlparse.parse_qs(compiled_postdata, keep_blank_values=True)

        for key, val in all_upload_params.iteritems():
            all_upload_params[key] = val[0]

        all_upload_params['data'] = open(img_file, 'rb')
        datagen, headers = multipart_encode(all_upload_params)
        request = urllib2.Request(url, datagen, headers)

        try:
            respdata = urllib2.urlopen(request).read()
        except urllib2.HTTPError, ex:
            return 'Received error code: ', ex.code

        return self.parse_response(respdata)
        
register_openers()

CONSUMER_KEY = ''
CONSUMER_SECRET = ''
OAUTH_TOKEN = ''
OAUTH_TOKEN_SECRET = ''

DIR = 'dir/with/pictures'
FILE_MASK = '*.jpg'
BLOG = 'blog here'


api = TumblrAPIv2(CONSUMER_KEY, CONSUMER_SECRET, OAUTH_TOKEN, OAUTH_TOKEN_SECRET)

for img in glob.glob( os.path.join(DIR, FILE_MASK) ):

    date  = time.gmtime(os.path.getmtime(img))
    post = {
        'type' : 'photo',
        'date' : time.strftime ("%Y-%m-%d %H:%M:%S", date),
        'data' : img,
        'tags' : time.strftime ("%Y", date) + ", photo",
        'caption' : time.strftime ("%B %d / %Y", date)
    }

    try:
        response = api.createPhotoPost(BLOG,post)
        if 'id' in response:
            print response['id']
            os.remove(img)
        else:
            print response
            break
            
    except APIError:
        print "Error"
        break

print "Done!"

Here's what I did to make this work for photosets (multiple photos for one post):
https://gist.github.com/charlesbrandt/11eadaec114288d621fa

What is 'PIN' supposed to be?

$ python auth.py
Request Token:
    - oauth_token        = HNeepB644EtQcUTWGsSlhYZgQ0Z8Hg8kkI0XNqDR4x8Qyjl0Qa
    - oauth_token_secret = <secret key>

Go to the following link in your browser:
http://www.tumblr.com/oauth/authorize?oauth_token=HNeepB644EtQcUTWGsSlhYZgQ0Z8Hg8kkI0XNqDR4x8Qyjl0Qa

Have you authorized me? (y/n) y
What is the PIN?

My callback URL is just tumblr.com as I don't have a site for a test like this.

Worked like a charm!! Thanks velocityzen!