Quote from NatCrit20 >>

 "the duplicates move with you and mimic your actions, shifting position so it's impossible to track which image is real."

Does this mean that any image can get closer to the enemy, away from the enemy, or flank? I am confused on how a person who casts this spell, how can they position them. Also HOW FAR can they be apart from each other.. That isn't specified lol

The line before that indicates they appear in your space, ie, less than five feet from you. They move with your movement (and not away/towards you if you're staying still), and they shift position with each other, meaning they can't "shift" into positions outside of your space.

If you're looking for the effect you're describing, the Trickery Cleric's Invoke Duplicity does the job (and you always have this spell prepared too!).

"Each time a creature targets you with an attack during the spell's duration, roll a d20 to determine whether the attack instead targets one of your duplicates."

Does it mean I have to do it before I know the attack roll? Or can I decide after, if I see I woule actually be hit?

Quote from Drenix >>

"Each time a creature targets you with an attack during the spell's duration, roll a d20 to determine whether the attack instead targets one of your duplicates."

Does it mean I have to do it before I know the attack roll? Or can I decide after, if I see I woule actually be hit?

So the way this works is that when the enemy declares you as the target for an attack, you roll a d20 to determine if the attack is at you or one of your duplicates. Once determined who the attack is hitting then the attack roll would be contested by your AC or your duplicates. With the phrasing "Each time a creature targets you with an attack" means that any attack targeting you is subject to the spell. This is ultimately the magic shell game once you cast it your mixed up with your duplicates and the d20 roll is whether or not the attack got the right one.

TL;DR: Yes you have to roll it as soon as they target you to see who the attack is going to actually target you/duplicates.

I absolutely love this spell the fact that you can annoy your DM by saying that no that hits my duplicate is hilarious 

Casting word is:

Picturium Reflectus

How accurate/complete are the mirror images?

Wouldn't a creature like an orc or something detect a phony by scent (or lack of it)?

For all purposes, the mirror images are all inside the same square as you and partially overlap. They really aren't so far apart that you could inspect them individually, and because they are constantly shifting pinning down the real one is very hard.

The spell very clearly states when a creature is not affected. Any creature could close their eyes (effectively being blinded with the according penalties) to ignore the duplicates.

Orcs by the way have no scent as keen to do something by the way. It would need to specifically state in a creature's profile that it uses senses other than sight.

Quote from Narokh >>

It would need to specifically state in a creature's profile that it uses senses other than sight.

 I don't mean "solely rely on".  I mean, "in addition to sight".  Humans rely mainly on sight, because we evolved in an environment where that was the most useful.  Dogs & cats (to name just two) rely heavily on scent.  And orcs, trolls, bugbears, & many other monsters aren't human...so could they, would they, notice something _humans_ (who rely mainly on sight) wouldn't?

Thats not how scent works. Especially in a fight, as air is turbulent, it would be impossible to figure out that two of those things dont have scent.

Also, your Orc doesnt rely on scent otherwise, so why would they now? Of course, if they have some magical smellivision (like blindsight or tremorsense), then yeah, it would fall under "A creature is unaffected by this spell […] if it relies on senses other than sight"

Scent is good for tracking over long distances, knowing who's territory you're in and reading the physical conditions of people around you. Thats why blind cats will still run into you, as will blind dogs (there's plenty of proof for that on youtube).

You might be able to make an argument for sound, and either way: If you have blindsight because  you can hear really good, smell really good or feel the air or whatever - blindsight stays blindsight. Unless your Orcs have blindsight, they dont have blindsight.

Maybe, if you've got a real sniffler, relying on scent would let you "see" up to ten feet away and heavily obscure anything within that radius.

And a simple in-world explanation: The nature of illusory magic is such that even when all you can do is see it, it alters your perception, rendering instincts and honed skill nearly useless (nearly, as represented by saving throws or the D20 in this case)

Quote from THEFINISHER02 >>

Would someone be able to know which one is the real on with investigation?

 

 Even if investigation check was a single action check (which I would say it is not normally), that would work for about .1 seconds.  Then the images merge and flow together, completely making your investigation check useless.

because that's some unfair BS

Not a concentration spell, they persist and mimic your current state.  Could prevent a death save if they're attacked instead of you.

How does Mirror Image effect spells such as Bane? The party is split almost 50/50, we're all born again players (havent played since 3.5). Bane isnt an attack, but you do have to select targets so... looking for some insight. Thanks.

This spell has a lot of flavor text. The important part is that it takes effect "each time a creature targets you with an attack" - it says nothing about being targeted by other effects. Otherwise it would say something like, each time a creature targets you with a harmful effect.

So I would rule that bane would function as normal. 

Wait, so if you cast this spell one turn and then cast it again the next turn, does it stack? that seems pretty powerful to me if it does.

The rules for this are in the PHB, Chapter 10, in the Combining Magical Effects part= "The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect — such as the highest bonus — from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.

For example, if two clerics cast bless on the same target, that character gains the spell's benefit only once; he or she doesn't get to roll two bonus dice."

However, this is where it gets a bit more interesting (based upon the small amount of research I've done). Under your example, the 2nd one would apply over the 1st, because it is the most recent casting. However this does not end the effect of your 1st casting and where we start delving into the "Instead, the most potent effect — such as the highest bonus — from those castings applies while their durations overlap..." If one of the images from the 2nd casting gets hits, then its possible the effect would switch back to the 1st casting, as it would have all of its images still and therefore be the spell with the most potent effect. As images are defeated, the active spell would be swapped for the one which had the most images left, favoring the 2nd casting in the case of a tie.

Of course, anything like this would ultimately be up to the GM's interpretations and decision.

Quote from Lasthope64 >>

The rules for this are in the PHB, Chapter 10, in the Combining Magical Effects part =
"The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect — such as the highest bonus — from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.
For example, if two clerics cast bless on the same target, that character gains the spell's benefit only once; he or she doesn't get to roll two bonus dice."

However, this is where it gets a bit more interesting (based upon the small amount of research I've done). Under your example, the 2nd one would apply over the 1st, because it is the most recent casting. However this does not end the effect of your 1st casting and where we start delving into the "Instead, the most potent effect — such as the highest bonus — from those castings applies while their durations overlap..." If one of the images from the 2nd casting gets hits, then its possible the effect would switch back to the 1st casting, as it would have all of its images still and therefore be the spell with the most potent effect. As images are defeated, the active spell would be swapped for the one which had the most images left, favoring the 2nd casting in the case of a tie.

Wait, that... adds up. Holy crap, what?
So long, Attack rolls. Tell your friend Damage I'm sorry they missed me.

It doesn't actually add up. Reason being the more potent effect is at time of casting. Since the second casting lasts longer, it overides the first and youR minute starts over, at which point the first casting goes poof. So no, it doesn't stack just like no other buff does.

If you cast again, first casting is cancelled and replaced with a minute long fresh casting with three images.

Quote from Bobthe88th >>

It doesn't actually add up. Reason being the more potent effect is at time of casting. Since the second casting lasts longer, it overides the first and youR minute starts over, at which point the first casting goes poof. So no, it doesn't stack just like no other buff does.

If you cast again, first casting is cancelled and replaced with a minute long fresh casting with three images.

 Nope: Your first casting explicitly does not "go poof": The two spells overlap.

"the most potent effect — such as the highest bonus — from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap"

Even if the quantified "potency" is assumed to be a one-time measurement (any RAW or Sage Advice to support this?), & therefore the "most potent" priority would not flip-flop between the two castings as their bonuses wore down, you would then still have the full benefit of the first casting taking effect when the second wears out.

I see two viable interpretations, based on RAW & Sage Advice on the topic of overlapping spells:
1) (This assumes that "potency" is not fixated at the time of casting.) If you cast Mirror Image twice, you still have 3 duplicates; if one gets hit it disappears, the "potency" drops, & your second casting takes effect, giving you three duplicates; & so on, flipping back & forth between the two castings until all duplicates are hit. 6 duplicates in total.
2) (This assumes that "potency" is fixated at the time of casting.) If you cast Mirror Image twice, you still have 3 duplicates; if one gets hit it disappears; when all 3 disappear, that casting of the spell ends; your "lower potency" casting goes into effect and you have 3 duplicates left. 6 duplicates in total.

I see no viable interpretation in which casting this spell twice ends the first casting; thus far, that is not how overlapping spells work in 5e.

Quote from Ligabytes >>

Quote from THEFINISHER02 >>

Would someone be able to know which one is the real on with investigation?

 

 Even if investigation check was a single action check (which I would say it is not normally), that would work for about .1 seconds.  Then the images merge and flow together, completely making your investigation check useless.

 their is a an investigate action, but your point still stands