Using mixed case shortened URLs I have a content type Advert, which have image and URL fields and I put it in a block to place it on the page. 

All works fine EXCEPT when the advertiser provides a mixed case Bit.ly shortened link to their site, Drupal is converting it to lower case but Bit.ly is case sensitive and either does not find the link at all or it redirect to another . How can I force Drupal to retain the mixed case URL, at least for external URLs? The Bit.ly link is important as the advertiser uses it to track ad clicks and hence the performance of the advert on our site
Doh, what a dummy! I missed an option in rewrite results on the image field to set output as link with no transform!

Thanks everybody.