Response.BinaryWrite not working in Firefox and Chrome

hi all!
please help!
I have binary data - it is png picture. 
I use   Response.BinaryWrite to display this picture.
Unfortunately it works only in Internet Explorer. In Firefox and Chrome it shows long text of strange symbols.
 
What's wrong with BinaryWrite? How to solve this?
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I may not say to asp:Image to show this picture, I may not indicate ImageURL, becouse there's no URL. This picture is response from webrequest. And webrequest may not be indicated in URL because I set some parameters not in QueryString but in post data.

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