<td align="center">
<!-- desktop version -->
         <img src="https://via.placeholder.com/600x600?text=Desktop" alt="" width="600"     height="600" style="display: block;" class="nomob">
<!-- end desktop version -->	
<!-- mobile version -->
<span style="mso-element:field-begin;"></span> 
<div style="display:none;" class="show">
	<img src="https://via.placeholder.com/600x600?text=mobile" alt="" width="300" height="300" style="display: none;" class="show">
<span style="mso-element:field-end;"></span>
<!-- end mobile version -->
@media screen and (max-device-width:640px), screen and (max-width:640px) {
    .nomob {display: none!important;}
    .show {display: block!important;}

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