If you've created ads outside of the MNTN platform that you'd like to upload to your account, you may use either the Static Upload option in the Creative Library or use the Upload Static Creative option in the Multi-Touch step of the campaign workflow. 200KB is the maximum file size for static uploads.
After selecting this option, you'll be shown a quick upload page, where you can drag-n-drop your Multi-Touch ads. You may upload any mix of our 22 supported ad sizes, though we recommend you upload at minimum the 300x250, 728x90, 300x50, 320x50, 300x600, and 160x600 ad sizes.
When you're done, your creative will be saved to your My Creative folder in the creative tab and will be eligible for use on any campaign.