1) From your own Profile, you can quickly delete individual images by clicking on the trash icon in the bottom right hand corner of each image.

You can also bulk delete (multiple images) by (1) clicking "Select Images", (2) clicking on all the images you want deleted and (3) clicking the "Delete" button.

2) From the Canvas view, select Move/Select ("V") first and then click on the given image. Then, click on the trash icon to Delete the image. Alternatively, you can just press "Delete" after you select the image as a keyboard shortcut for deletion.

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

3) From the Board view, hover over a given image and then click the trash icon in the bottom right corner.