Web browser cannot find files on server

I uploaded a couple of pictures to our web site server.

When I copy the URL into a document in the format http:\\www.wmcohs\images\filename.jpg, it does not find the file. This format works for other files in that directory.

When Iuse the "copy url - ftp" format, with login information it can find and display the picture, eg.
ftp://username:password@ ... lename.JPG it does find and display the picture.

How do you find and display the files in the http format? Is there a security feature or publish feature that needs to be turned on to find the files?