Need Help w/ Slideshow Picture Quality & Music Syncing

I recently designed my first slideshow DVD & burnt it to watch on my TV. I set the ratio to 16:9 for my widescreen TV but the photo's were in the center of the screen and did not fill the screen. The pictures are all 10+ megapixel in size. Also, even though they don't take up even 1/2 the screen, they are still rather grainy. Is there a way to improve the quality of the picture &/or increase the size to fill the screen.

Also, when playing the DVD on my TV, there were slight delays from Menu transition to slide show; as well as a few second delay from slideshow beginning to the start of my audio selection. Any ideas on how to improve these issues?

Thanks in advance to who ever can help...