Seat cover for dining chair. Clean, simple wrap around design that fits snugly around legs with velcro. This would be simple to make by altering this DIY: http://www.athomeonthebay.com/2012/03/dining-chair-drop-cloth-slipcovers.html
How to Reupholster a Dining Chair Seat: DIY Tutorial full of tips and tricks. Gotta love this "no-mess method" that eliminates the most grueling steps of any reupholstery project! Keep the original seat intact and simply add a new cushion and fabric atop it! The folding method works great for square-edged chairs like this one.