- You should prepare images before uploading (I recommend disabling image resizing, this is for novice users and causes issues in some cases). Prepare images at 640 x 330 pixels for the half-width slider and 980 x 330 pixels for the full-width.
(if you don’t have Photoshop or Illustrator find a free alternative graphics editor here: http://www.gimp.org/)

- It is important to prepare lightweight graphics, this could mean saving as gif, png or a lower quality jpg.

- I would say keep the slides to a very minimum of key features only. Even if there wasn’t an issue of speed, marketing wise you don’t want to have too many slides.

Thanks, Bryan