@Cirrus Light  
Even if the creators don’t have a specific size in mind, it’d be rather strange for them to be canonically measured in scales of microns or lightyears. Some sizes are more intuitively reasonable to a human from a given culture than other sizes. The rules determining this are flexible and extremely difficult to define or explain in detail, but clearly exist on some level, and presumably are considerably tighter than my blatantly exaggerated lower/upper limits.

@Cirrus Light  
Ill never understand why people would disagree. There is no evidence to suggest that they are full sized ponies, Apart from that littlest petshop advert and using 2 completely different styles of animation is not a good comparison. Especially since the humans in littlest petshop have giant heads that make up a 3rd of their body.

@Background Pony #24B6  
Surprising if you go into it thinking the creators didn’t have a specific size in mind. But despite the show’s inconsistency in other areas, in this way in particular, it has been rather consistent.

@Cirrus Light  
Surprising in what way?  
There are countless intuited data points throughout the show against which to compare them. Most of them are extremely fuzzy data points, but ought all point to some reasonably consistent average, or else the show will look vaguely “off” to anyone watching. And since it’s mostly all done in Flash, everything can be kept consistent with precedent by exact scaling values and trivial numerical tweaks.

@mycarhasaMoustache  
Ah, well, usually “here you go again” means someone disagrees :q

@Cirrus Light  
Ive already said It I agree. I was not arguing against it. Lets face it its literally in the title of the show, My LITTLE pony. Why anyone would take the title and assume they are full sized makes no sense at all. The only pony on the show that would be full size would be Celestia. Everypony else is small.

@Background Pony #3A5F  
You’re entitled to your own opinions.
 
But not to your own facts.
 
And the facts are as I listed.
 
I mean, they’re not real, so you can imagine them differently sized in some fanfiction, but that’s not what the source material would indicate. That’d be kinda AU. But the point here is seeing what canon would be. And we basically already have it with Rainbow riding Rainbow and the EQG intro tranformation (both indicating 3-4 feet).
 
At this point I’m kinda just amazed anyone could be so sure of themselves in views so blatantly contrary to such overwhelming evidence.

@Cirrus Light  
Here you go again.

I don’t understand how there can even be an argument when we have what are effectively empirical data points;
 

 
The best one is the one I called “EQG Doorframe”, since there is a standard size for doorframes, and even if that’s off, late-teen girls should be about 5’6”, anyways, but Angel will be the same size in both worlds since bunnies exist normally in both, so it’s more or less a nail in the coffin to any other theories on pony sizes.
 
Source for doorframe work:
 

 
We also have the “eight foot candy cane”, and I saw a graphic comparing the size of ponies against butterflies that fly around them at some points in the show. That method is admittedly less vetted than the others. This was done in the doorframe image above, but I’ve also done it on my own more succinctly here, too.
 
There’s also the “Apple Theory” which uses the average size of apples with the apples we see in the show and compares them to Applejack (who’s standing next to them in that frame). Again, also used in the doorframe image, but I’m going to put the image here, too, just to show the work:  

 
There’s also, as someone mentioned, the bloopers reel:
 

 
Also the intro to EQG has this:
 

 
For an average 5’6” young woman/late teen, that means the ponies are around 3’5”
 
Finally, we also have this:
 

 
and this screencap:
 

 
both giving right around - just under 4 feet.
 
And now of course, we also have this image I’m commenting on, here.
 

 
They are in-between 3 and 4 feet. At this point, it’s not a matter of opinion or headcanon, given the sheer amount of proofs we’ve had of this range.
 
And it seems the creators are very surprisingly consistent about that.
 
But given the sheer amount of proofs of the 3-4 foot range, anything that points to a different size is basically a data scatter unless a few of them start to pile up.

@raakamagna  
Dont ask me I was not the one debating it.

@northern haste  
I was not the one that brought it up. Regardless. It dose show that littlest petshop humans have massive heads and tiny bodies.

Yes because using littlest pet shop a show with a completely different art style is such a great comparison

@mycarhasaMoustache  
How? we got canon info. That should be enough.

@raakamagna  
Sadly its still going on.

This debate should be over with the self parody blooper reel o Rainbow Dash flying on Rainbow Dash.