Gravity Wiz // Gravity Forms // Preview Image of File Upload

gw-image-preview.html

<div id="preview" style="display:none;">
	<img src="" style="width:150px;">
</div>

gw-image-preview.js

/**
 * Gravity Wiz // Gravity Forms // Preview Image of File Upload
 *
 * Outputs an image preview for File Upload fields.
 * 
 * Based on: https://stackoverflow.com/questions/37880725/gravity-form-preview-of-image-upload
 */
( function( $ ) { 
    
    // Update "123" to Form ID and "1" to File Upload Field ID in "#input_123_1".
    $( document ).on( "change","#input_123_1", function() {
	readURL( this );
    } );
    
    function readURL( input ) {
    
	if ( input.files && input.files[0] ) {
    
	    var reader = new FileReader();
	    $( '#preview' ).show();
    
	    reader.onload = function ( e ) {
		$( '#preview>img' ).attr( 'src', e.target.result );
	    }
    
	    reader.readAsDataURL( input.files[0] );

	}    
    
    }

} )( jQuery )