Site Logo: Between 60px and 100px high, and between 200px and 400px wide.
Home slideshow: Most SilkStart sites have a homepage slideshow. The dimensions for this can be edited in Admin Panel > Site > Slideshows. Once you set the height and width of your slideshow, be sure that each the dimensions of each slideshow image you upload match the size of the slider.
Banner images (Premium theme): 1600px wide. We recommend any image between 1200px wide and 2000px wide. Most new SilkStart sites require images 1600x500px.
Team Page: 400x400px
Articles (featured image): 400x400px