Make the time and do it right. Get those new pieces finished and have them professionally photographed. It isn't possible to put too much emphasis on this one point. Good slides have clarity, simplicity, easy to see details, and a pleasing background that complements the work. They show off your work and tell potential buyers a lot about the quality of your designs.
Poor slides do the same thing, but in a negative way.
Don't leave this crucial element of your ad to chance. Think of how exciting it will be for buyers to see work as different as yours. And remember, each year's DJS is a unique book. The mix of work is never the same two years in a row. Many people stay in year after year, but there are always newcomers, too.