1) From your own Profile, you can quickly download individual images by clicking on the Download icon in the upper left hand corner of each image.

You can also bulk download (multiple images) by (1) clicking "Select Images", (2) clicking on all the images you want downloaded and (3) clicking the "Download" button. You can bulk select all images in between two given images by clicking on the first image and then clicking Shift+click on the second image.

2) From the Canvas view, select Move/Select ("V") first and then click on the given image. A panel will appear on the right side of the page and on the bottom of the page you'll see a download icon which you can click to download the image. Alternatively, you can just press "D" after you select the image as a keyboard shortcut for downloading.

You can also right click on a given image and a "Download" option will appear in the menu.

3) From the Board view, hover over a given image and then click the Download icon in the top left corner.

4) From the Community Feed pages, you can save an image by clicking on them to bring up the detailed view and then click download: