Inspired by Zed (from League of Legends) and Blake (RWBY season 3 hype). The Dimensional feats were also an inspiration, though I've got the route of branches than just one tall tree.
These feats intended for Ninjas (originally planned as an archetype), though most may be accessed by most any arcane caster (though the Magus and Bloodrager will get better mileage), or a rogue that chooses to pick up a ki pool.
Finally, the feats have not been playtested. I welcome feedback regarding balance points.
After Image (General)
You can leave behind images as distractions.
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image.
Benefit: When using shadow clone or casting mirror image, you create one additional image. You can also leave an image behind in any square you move through as a free action. This image can continue to mimic your actions or remain still but cannot leave the square, and can be destroyed by any attack targeting it (treat it as having your AC with only size modifiers).
Special: This feat can be selected in place of a ninja trick.
Distracting Image (Combat)
You can turn your images into harmful shadows.
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image, After Image.
Benefit: When using shadow clone or casting mirror image, you create one additional image. You can flank with your images.
Special: This feat can be selected in place of a ninja trick.
Sharp Image (Combat)
You can turn your images into harmful shadows.
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image, Sneak attack +3d6, After Image.
Benefit: When using shadow clone or casting mirror image, you create one additional image. Whenever one of your images is destroyed by a melee attack, you can spend an immediate action to cause the image to turn quasi-real and strike the attacker, dealing slashing damage equal to your sneak attack dice.
Special: This feat can be selected in place of a ninja trick.
Ensnaring Image (Combat)
You can turn your images into entangling shadows.
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image, Sneak attack +5d6, After Image.
Benefit: When using shadow clone or casting mirror image, you create one additional image. Whenever one of your images deals damage to a creature or a creature enters its square, that creature gains the entangled condition for 1 minute. Entangled creatures can attempt to break free as a move action, making a Strength or Escape Artist check. The DC for this check is equal to 10 + 1/2 your HD + your number of sneak attack dice.
Special: This feat can be selected in place of a ninja trick.
Reverse Image (Combat)
You can return to an image to surprise your foes.
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image, After Image, base attack bonus +5.
Benefit: When using shadow clone or casting mirror image, you create one additional image. You can as a move action instantly transport yourself to any square you have an image in (this destroys that image). Opponents are flat-footed against any attacks you make until the end of your turn.
Special: This feat can be selected in place of a ninja trick.
Threatening Image (Combat)
You can swiftly punish anyone that lowers their guard around your images
Prerequisites: Ability to use the shadow clone ninja trick or cast mirror image, After Image, Reverse Image, base attack bonus +9.
Benefit: When using shadow clone or casting mirror image, you create one additional image. If an opponent adjacent to one of your images tries to leave the square without taking a 5-foot-step or withdraw action, or tries to cast a spell without casting defensively, you can transport yourself to that image as a free action to make an attack of opportunity. The provoking opponent is flat-footed against your attack of opportunity.
Special: This feat can be selected in place of a ninja trick.
That is a cool idea.
I think you should expand a bit on how After Image works. What happens if someone enters a square with a mirror image? What happens if the caster enters a square--can she pick up images left behind? Do opponents know that it is an illusion (probably if they can also see the real caster, but if they only see the image and not the real caster, it might fool them). Does the caster have any control over her after image (probably not, but you could create an additional feat that would allow it to work similar to mislead)?
Also, keep in mind that figments cannot produce real effects (like damaging opponents), so there should be some flavor text mentioning how you infuse these images with shadow stuff or something like that.