Saving images from a web page
import os, re, urllib

def Read(url):


Python convention is to name function lowercase_with_underscores

    uopen = urllib.urlopen(url)


I recommend against abbreviations

    uread = ''
    for line in uopen: uread += line
    return uread


Use uopen.read() it'll read the whole file

def Find(what, where):
    found = re.findall(what, where)
    match = []
    for i in found:


avoid single letter variable names

        i = i[9:-1]
        match.append(i)
    return match   


Combine short lines of code

 for i in re.findall(what, where):
      match.append(i[9:-1])


I think its cleaner this way. Also use capturing groups rather then indexes.

def Retrieve(urls, loc):
    loc = os.path.realpath(loc)
    os.system('mkdir ' + loc +'/picretrieved')


Use os.mkdir rather than using system

    loc += '/picretrieved'


Use os.path.join to construct paths

    x = 0
    exts = ['.jpeg', '.jpg', '.gif', '.png']
    for url in urls:
        x += 1


use for x, url in enumerate(urls):

        for i in exts:
            ext = re.search(i, url)


Don't use regular expressions to search for simple strings. In this case I think you really want to use url.endswith(i). Also, stop using i everywhere.

            if ext != None:
                ext = ext.group()
                urllib.urlretrieve(url, loc + '/' + str(x) + ext)
            else:
                continue


This continue does nothing

    print 'Placed', str(x), 'pictures in:', loc


You don't need to use str when you are using print. It does it automatically.

def main():
    url = raw_input('URL to PicRetrieve (google.com): ')
    url = 'http://' + url
    loc = raw_input('Location for PicRetrieve older ("." for here): ')
    html = Read(url)
    urls = Find('img src=".*?"',  html)


Generally, using an html parser is preferred to using a regex on html. In this simple case you are ok.

    print urls
    Retrieve(urls, loc)


if __name__ == '__main__':
    main()