I'm having trouble using the auto-resize feature on a few ad sizes?
There will sometimes be some sizes that don't fit perfectly while we optimize the tech (this will be ongoing). There is a workaround for now: while you are viewing the size that looks abnormal (e.g. 320x50), you can click the edit button and redesign that specific size (this won't affect other sizes unless perfectly proportionate to the size you're editing). This way you can use the master tab to create your 3 designs, re-size 90% of the other sizes, and then do 1-3 other designs for sizes that are not to your liking.
For more information, see our demo video on how to resize static ads.