Sure it can be done, there are a couple of ways to approach this.
Journey Builder method - requires setting up all different Emails prior. In the Journey you would be using the Random Split activity where you can define up to 10 different paths per activity, where the distribution then happens at random.
This method is probably the easiest as it requires no scripting. For statistical purposes this is would be a mess to deal with though.
AMPScript Random() method - requires using the Random() function to define a random integer between your number of variations (1 - 12) where, depending on the integer selected, a Dynamic Content piece is shown in the Email.
Essentially you set a variable to be an integer from
Random() and depending on the integer set you can have AMPscript showing a different image content with simple
IF condition set.
VAR @random, @num1, @num2
SET @num1 = 1
SET @num2 = 2
SET @random = random(@num1, @num2)
%%[IF @random == "1" THEN ]%%
%%[IF @random =="2" THEN ]%%