Python - quickly update urls in a web page

# update a webpages url references. 
# Your web page has a collection of images and you 
# want to update all the "folder1" references 
# to the new folder you've populated called "newfolder" 
 
# normally you would open the actual html file 
# and iterate through the file one line at a time 
# like in this post.  
 
# but for simplicity sake lets just use a multi line string 
# for the example 
theString = """ <img src="folder1/pic2324.jpg" /> 
<img src="folder1/pic2255.png" /> 
<img src="folder2/pic552.jpg" /> 
<img src="folder1/pica2f.jpg" /> 
 
""" 
 
# all you need is to iterate through the 
# file and replace 'folder1' with 'newfolder' 
for line in theString.split('\n'):
    line = line.replace("folder1/", "newfolder/")
    print line
 
#output: 
#     <img src="newfolder/pic2324.jpg" /> 
#    <img src="newfolder/pic2255.png" /> 
#    <img src="folder2/pic552.jpg" /> 
#    <img src="newfolder/pica2f.jpg" />