I HAVE 11 IMAGES THAT NEEDS TO APPEAR ON THE EMAIL DEPENDING ON THE CUSTOMER.
wHAT IS THE BEST WAY AND EASIEST WAY TO APPLY THIS IN MARKETO EMAILS?
Well, "best" and "easiest" are subjective -- and often contradictory!
You can make an image dynamic by clicking it and choosing Make Dynamic. This is GUI-driven and probably "best" for you. Of course it has to be linked to a Segmentation or it won't work -- so you're getting ahead of yourself if you don't already have a Segmentation + Segments set up to address the "depending on the customer" part.
You can use Velocity to outputtags directly. To me this is "best" because I've never been fond of the Make Dynamic experience, and it doesn't require a Segmentation. But you have to be comfortable with at least basic Velocity coding.
Also please turn off Caps Lock, thanks.