[VE][108] Error Message Feedback

Validating http://www.whereartmeetstheheart.com/wendyxoot.html
Error [108]: "there is no attribute X"

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Follow the instructions at
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   1. Error /Line 33 column 152/: there is no attribute "oncontextmenu".

|..." style="border: 0px;" oncontextmenu=*"*return false;" galleryimg="no" onmoused|

      You have used the attribute named above in your document, but the
      document type you are using does not support that attribute for
      this element. This error is often caused by incorrect use of the
      "Strict" document type with a document that uses frames (e.g. you
      must use the "Transitional" document type to get the "target"
      attribute), or by using vendor proprietary extensions such as
      "marginheight" (this is usually fixed by using CSS to achieve the
      desired effect instead).

      This error may also result if the element itself is not supported
      in the document type you are using, as an undefined element will
      have no supported attributes; in this case, see the
      element-undefined error message for further information.

      How to fix: check the spelling and case of the element and
      attribute, (Remember XHTML is all lower-case) and/or check that
      they are both allowed in the chosen document type, and/or use CSS
      instead of this attribute.

      ? <feedback.html?uri=;errmsg_id=108#errormsg>

   2. Error /Line 33 column 179/: there is no attribute "galleryimg".

|...ntextmenu="return false;" galleryimg=*"*no" onmousedown="return false;" onmouse|

      ? <feedback.html?uri=;errmsg_id=108#errormsg>



I get the above error messages for "oncontextmenu" and "galleryimg".  I 
have an Art site and want to protect my images from being downloaded.  
The above two attributes are intended to prevent IE from showing the 
little icons that automatically appear onmouseover and allow an image to 
be saved, emailed, printed, etc.  The code works but gives me a 
validation error with a response that using CSS would eliminate the 
error, however, I can't find any CSS code to accomplish the desired 
action.  Since I am trying to be XHTML 1.1 compliant, could you please 
direct me to something that will resolve my problem - CSS or otherwise?

Thanks,

Phil Huntley-Franck
www.whereartmeetstheheart.com