400 errors and URL parameters in Google Webmaster Tools

[James77]

On our website we do a lot of dynamic resizing of images by using a script which automatically re-sizes an image dependant on paramaters in the URL like:

www.mysite.com/images/1234.jpg?width=100&height=200&cut=false

In webmaster tools I have noticed there are a lot of 400 errors on these image

Also when I click the URL's listed as causing the errors the URL's are URL Encoded and go to pages like this (this give a bad request):

www.mysite.com/images/1234.jpg?%3Fwidth%3D100%26height%3D200%26cut%3Dfalse

What are your thoughts on what I should do to stop this?

I notice in my webmaster tools "URL Parameters" there are parameters for:
height
width
cut

which must be from the Image URLs.

These are currently set to "Let Google Decide", but should I change them manually to "Doesn't effect page content"?

Thanks in advance

[STPseo]

The easiest way would be to add a disallow line to your robots.txt file.

From Google:

• To block access to all URLs that include a question mark (?) (more specifically, any URL that begins with your domain name, followed by any string, followed by a question mark, followed by any string):```
  User-agent: Googlebot
  Disallow: /*?

More info: http://www.google.com/support/webmasters/bin/answer.py?answer=156449