Projects images will automatically resize down to 1200px when uploaded. However, if you’ve uploaded an image greater than 1400px wide, you can choose to make that image “full bleed” or have it reach from edge to edge of the project page.
When you upload an image wider that 1400px wide, you’ll see an arrow in the top right corner of the image. Clicking that arrow will make the image full bleed. No more fussing with background alignments or mobile error.