Combine pictures into one
Upload a photo and select the canvas size to combine your pictures. For instance, unlink the aspect ratio and enter a 1800x1200 resolution (3:2). Click "pad" or "crop" to adjust the picture to the canvas, or set a border to adjust with margin.
Then, resize your photo to fill a half of the canvas (900x1200). Use the corner handlers for scaling and the middle ones for cropping. Make "double click" on the image to adjust the cropping area, moving the image around the visible area.