Image Wrapper for thumbnails

Yup, it’s possible. You’ll need two custom functions which contain the wrapping markup. They should be hooked into woocommerce_before_shop_loop_item_title with the appropriate priorities. You can see here that the thumbnail is hooked in with a priority of 10. So try something like 5 for your opening tag and 15 for the closing tag.

Cheers

add_action( 'woocommerce_before_shop_loop_item_title', 'jk_image_wrapper_open', 5 );
add_action( 'woocommerce_before_shop_loop_item_title', 'jk_image_wrapper_close', 15 );

function jk_image_wrapper_open() {
echo '<div class="img-wrap">';
}

function jk_image_wrapper_close() {
echo '</div>';
}

Give that a try.