What is the optimal image size for small and medium ads?

[usmf]

What is the optimal image size (pixels or inches) for the different size options when adding an advertisement image? Thanks!

[CoffeeCake]

The Interactive Advertising Bureau defines standards for sizes and other properties related to internet advertising. See: https://www.iab.com/guidelines/iab-new-ad-portfolio/

[usmf]

Thanks. I'll see if I can check that out, though I think it needs me to make an account.