Do you want to download all images in 1 x as a ZIP file? Then click on the cogwheel at the far right in the grey bar below and choose to download all files (.zip).
Do you want to download some images at once? Move your mouse over the image and click on the selection box in the upper left corner of the image. Repeat this for all images you want to download. Then click on the cogwheel in the grey bar and choose download selected files (.zip).
Do you only want to download 1 image? Then move your mouse over the image and click on the dropdown icon in the upper right corner of the image and choose Download file.