JPEG Images

Thanks for the updated theme! I've been struggling for the past hour to add images to the home page slide show. I finally figured out that all of the images I currently own seem to be too small or JPEG instead of JPG.

Is there a way to get the theme to accept JPEG images?

Also, what size do I need to make my logo so that there is no distortion once I upload it? Can I change the size of the logo image?