Django and Captcha images

from django.shortcuts import render_to_response
from os import remove
def captcha(request):
		# random generator
		from random import choice
		# PIL elements, sha for hash
		import Image, ImageDraw, ImageFont, sha
		# create a 5 char random strin and sha hash it, note that there is no big i
		SALT = settings.SECRET_KEY[:20]
		imgtext = ''.join([choice('QWERTYUOPASDFGHJKLZXCVBNM') for i in range(5)])
		# create hash
		imghash = sha.new(SALT+imgtext).hexdigest()
		# create an image with the string (media is the folder with static files accessed by /site_media)
		# PIL "code" - open image, add text using font, save as new
		im=Image.open('media/bg.jpg')
		draw=ImageDraw.Draw(im)
		font=ImageFont.truetype('media/SHERWOOD.TTF', 18)
		draw.text((10,10),imgtext, font=font, fill=(100,100,50))
		# save as a temporary image
		# I use user IP for the filename, SITE_IMAGES_DIR_PATH - system path to folder for images
		temp = settings.SITE_IMAGES_DIR_PATH + request.META['REMOTE_ADDR'] + '.jpg'
		tempname = request.META['REMOTE_ADDR'] + '.jpg'
		im.save(temp, "JPEG")
		
		if request.POST:
			data = request.POST.copy()
			# does the captcha math ?
			if data['imghash'] == sha.new(SALT+data['imgtext']).hexdigest():
				# captcha ok
				# save data etc.
				# use another view/template in render_to_response and delete the temp captcha file:
				#remove(temp)
				return render_to_response('form.html', {'ok': True, 'hash': imghash, 'tempname': tempname})
			else:
				# captcha bad
				# return the form
				return render_to_response('form.html', {'error': True, 'hash': imghash, 'tempname': tempname})
		# no post data, show the form
		else:
			return render_to_response('form.html', {'hash': imghash, 'tempname': tempname})

{% if error %}
		<div style="text-align:center;"><b>FAILURE</b></div>
	{% endif %}
	{% if ok %}
		<div style="text-align:center;"><b>SUCCESS ! :)</b></div>
	{% endif %}
	<form action="." method="POST"><input type="hidden" value="{{ hash }}" name="imghash">
	<b>Text from the image</b><br />(Use CAPITAL letters)<br />
	<input type="text" size="20" name="imgtext"><br /><img src="/site_media/{{ tempname }}"><br />
	<br /><input type="submit" value="Send Form" class="actiontable">
	</form>

class LoginForm(forms.Manipulator):
	def __init__(self):
		self.fields = (forms.TextField(field_name="login", length=30, maxlength=200, is_required=True),
		forms.PasswordField(field_name="password", length=30, maxlength=200, is_required=True),
		forms.TextField(field_name="imgtext", is_required=True, validator_list=[self.hashcheck]),
		forms.TextField(field_name="imghash", is_required=True),)
	def hashcheck(self, field_data, all_data):
		import sha
		SALT = settings.SECRET_KEY[:20]
		if not all_data['imghash'] == sha.new(SALT+field_data).hexdigest():
			raise validators.ValidationError("Captcha Error.")

def loginlogout(request):
	from django.contrib.auth import authenticate, login
	if not request.user.is_authenticated():
		temp = settings.SITE_IMAGES_DIR_PATH + request.META['REMOTE_ADDR'] + '.jpg'
		tempname = request.META['REMOTE_ADDR'] + '.jpg'
		# captcha image creation
		from random import choice
		import Image, ImageDraw, ImageFont, sha
		# create a 5 char random strin and sha hash it
		SALT = settings.SECRET_KEY[:20]
		imgtext = ''.join([choice('QWERTYUOPASDFGHJKLZXCVBNM') for i in range(5)])
		imghash = sha.new(SALT+imgtext).hexdigest()
		# create an image with the string
		im=Image.open(settings.SITE_IMAGES_DIR_PATH + '../bg.jpg')
		draw=ImageDraw.Draw(im)
		font=ImageFont.truetype(settings.SITE_IMAGES_DIR_PATH + '../SHERWOOD.TTF', 24)
		draw.text((10,10),imgtext, font=font, fill=(100,100,50))
		im.save(temp,"JPEG")
		
		manipulator = LoginForm()
		# log in user
		if request.POST:
			data = request.POST.copy()
			errors = manipulator.get_validation_errors(data)
			if not errors:
				manipulator.do_html2python(data)
				user = authenticate(username=data['login'], password=data['password'])
				if user is not None:
					login(request, user)
					remove(temp)
					return HttpResponseRedirect("/user/")
				else:
					data['imgtext'] = ''
					form = forms.FormWrapper(manipulator, data, errors)
					return render_to_response('userpanel/' + settings.ENGINE + '/login.html', {'loginform': True, 'error': True, 'hash': imghash, 'form': form, 'theme': settings.THEME, 'engine': settings.ENGINE, 'temp':tempname})
		# no post data, show the login forum
		else:
			errors = data = {}
		form = forms.FormWrapper(manipulator, data, errors)
		return render_to_response('userpanel/' + settings.ENGINE + '/login.html', {'loginform': True, 'hash': imghash, 'form': form, 'theme': settings.THEME, 'engine': settings.ENGINE, 'temp':tempname})
	else:
		# user authenticated
		if request.GET:
			# logout user
			data = request.GET.copy()
			if data['log'] == 'out':
				from django.contrib.auth import logout
				logout(request)
				return HttpResponseRedirect("/user/")
		return HttpResponseRedirect("/user/")