First select the images you want to download and add them to the shopping cart by clicking on the cloud at the top of each product image.
Once you have added the desired images to your shopping cart, you can open your shopping cart by clicking on the shopping cart icon in the upper right corner of the window.
Select the desired download size and then click on Download Files in the upper left corner to download the desired images as a zip file. In the category product data you can download the product data as CSV export in addition to the images. Click on Download CSV Export on the right.
Note on using the shopping cart for product images: If you use the shopping cart function on the item detail page, you only download the displayed item image. If you use the shopping cart function in the catalog view, you download all item images (e.g. main image, backside, detail view).
Please note that the shopping cart is not saved. If you close the website or reload it, the shopping cart will be empty again.