iv>
            <label for="thumbnail" class="block text-sm font-medium text-gray-700">Course Thumbnail</label>
            <input type="file"
                   id="thumbnail"
                   name="thumbnail"
                   class="mt-1 block w-full text-sm text-gray-500 file:mr-4 file:py-2 file:px-4 file:rounded-md file:border-0 file:text-sm file:font-semibold file:bg-blue-50 file:text-blue-700 hover:file:bg-blue-100">
            <div id="thumbnail-preview" class="mt-2">
                {% if cours