How can I dynamically call an image using a token?

Fun problem!

You don't want to use program-level {{my.tokens}} here since a person's clan is set at a person level. Unless you have one email per clan or something - but it doesn't sound like that's your scenario. 

So if I a person can only have one clan, level, and name at a time then you want this to be written into a person's lead profile. You can do this via API 200 at a time using syncLeads (https://developers.marketo.com/rest-api/endpoint-reference/lead-database-endpoint-reference/#!/Leads/syncLeadUsingPOST) or via a csv/tsv upload in the Bulk API (https://developers.marketo.com/rest-api/bulk-import/). Either way, you will end up with something like this on each applicable person in Marketo:

First Name: Phil

Last Name: Wild

Clan: Example Clan

Level: Level 10

Img: example.com/1.jpg

If image is different for each user, put it on the person's record as per above. But if the image is based on clan (and therefore you have, say, only 10 different images) then I would use an inherited email script token from a top level program instead. Something like this:

#if( $clan = "clan1")

#set($image = "imagelocation1.com")

#elseif($clan = "clan2")

#set($image = "imagelocation2.com")

....

and so on. Better ways to do this but you get the idea. 

If you then set images at an inherited program level you can use those tokens everywhere, in every email, and if the image location changes you change it in one place. Not in every lead profile. 

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So overall you can tell your API team that they can either:

1) Do a bulk update of all relevant profiles in Marketo before a send, so everyone has the right info; or, ideally,

2) When someone is created, or their clan / details change, then update them in Marketo via the API. That way whenever you send an email their information will always be correct.

This is the best solution I can thing of, assuming you don't have an existing Salesforce / MS Dynamics sync that would do all of this automatically. Hope this helps!