감사해요~ 

/wp-content/plugins/kboard/skin/modern-gallery/editor.php 파일을 수정해주세요.

아래 코드를 지우거나 주석처리 하신 후

<div class="kboard-attr-file-wrap">
    <?php $attach_index = '1'; if(!$content->attach) $content->attach=array(); foreach($content->attach as $key => $attach):?>
    <div class="kboard-attr-row">
        <label class="attr-name">이미지</label>
        <div class="attr-value">
            <?php if($content->attach->{$key}[0]):?><?php echo $content->attach->{$key}[1]?> - <a href="<?php echo $url->getDeleteURLWithAttach($content->uid, $key);?>" onclick="return confirm('<?php echo __('Are you sure you want to delete?', 'kboard')?>');"><?php echo __('Delete file', 'kboard')?></a><?php endif?>
            <input type="file" name="kboard_attach_<?php echo $key?>">
        </div>
    </div>
    <?php $attach_index = intval(str_replace('file', '', $key)); $attach_index++; endforeach; ?>
    
    <div class="kboard-attr-row">
        <label class="attr-name">이미지</label>
        <div class="attr-value">
            <?php if(isset($content->attach->{'file'.$attach_index}[0]) && $content->attach->{'file'.$attach_index}[0]):?><?php echo $content->attach->{'file'.$attach_index}[1]?> - <a href="<?php echo $url->getDeleteURLWithAttach($content->uid, 'file'.$attach_index);?>" onclick="return confirm('<?php echo __('Are you sure you want to delete?', 'kboard')?>');"><?php echo __('Delete file', 'kboard')?></a><?php endif?>
            <input type="file" name="kboard_attach_file<?php echo $attach_index?>" onchange="add_input_file()">
        </div>
    </div>
</div>

아래 코드를 추가 해보세요.

default 스킨에 있는 코드 입니다^^

<div class="kboard-attr-row">
    <label class="attr-name"><?php echo __('Photos', 'kboard')?></label>
    <div class="attr-value">
        <a href="#" onclick="kboard_editor_open_media();return false;"><?php echo __('KBoard Add Media', 'kboard')?></a>
    </div>
</div>

<div class="kboard-attr-row">
    <label class="attr-name" for="kboard-input-thumbnail"><?php echo __('Thumbnail', 'kboard')?></label>
    <div class="attr-value">
        <?php if($content->thumbnail_file):?><?php echo $content->thumbnail_name?> - <a href="<?php echo $url->getDeleteURLWithAttach($content->uid);?>" onclick="return confirm('<?php echo __('Are you sure you want to delete?', 'kboard')?>');"><?php echo __('Delete file', 'kboard')?></a><?php endif?>
        <input type="file" id="kboard-input-thumbnail" name="thumbnail">
    </div>
</div>