Actually, I should clarify myself on this one. There are many different definitions of what a Hidden Mickey is. The most popular of these defines a Hidden Mickey as an actual Mickey, or the popular three-circle representation of Mickey, placed in the context of another Disney-owned property. For instance, in the live-action version of 101 Dalmatians, there is a shot in which you see a Mickey figurine in the background. Or, in the Tower of Terror, the stuffed Mickey the little girl is holding.
If the three-circle representation is used, then it needs to be in the proper proportions and shape. I shouldn't have added dimension as that can be anything as long as the proportions are maintained. (The two nickels and a quarter rule.) If its not, then how in the world does it even begin to represent Mickey?!
Of course, there can be other forms of Hidden Mickeys as well. Something that reflects some other aspect of Disney and is not even a Mickey at all. As an example, on the Disney Magic in Rockin Bar D, there is a series of musical notes plastered to the wall behind the bar. These notes are the music from Under the Sea. This, some would argue, is a Hidden Mickey because it represents a throwback to another part of the Disney Company without being obvious. It's a sort of stamp that states, "yes, this is Disney."
Of course, since the Walt Disney Company does not recognize any such thing as Hidden Mickeys, you could really argue anything you want. However, in my opinion, the smoke does not represent nor look like Mickey in any way. Thus, it's not a Hidden Mickey. Something that is not in the proper dimensions, shape, or proportion doesn't represent the Mouse.
Here are some ideas from HiddenMickey.org as to what a Hidden Mickey is: (Of course, as always, this is only one idea and not "official" or the "rule".)
"First of all, any Mickey that seems very large and elaborate or very intricate, such as the formations of a cave or even the shapes of the parks themselves, is probably not an honest-to-goodness Hidden Mickey. There are exceptions, of course, but few and far between.
Second, a Mickey should be proportioned correctly; while there is no "set" or "official" measurement for a Hidden Mickey, if the ears seem too small or too close together, like the padlocks in all the parks, or if each circle is a different size and not in perspective, it is most likely not a Hidden Mickey. (While Hidden Mickeys don't require the circles to be connected to one another, use good sense -- if they're very far apart like on the Big Thunder Gear, it's probably not convincing enough.) Also, be careful when looking that you aren't simply finding a group of circles. A Hidden Mickey should be unique to its surroundings; if there are bunches of balloons in a hand or round shapes on a light fixture, you are bound to see something that could qualify, but is most likely not an intentional Hidden Mickey. Of course, there are always exceptions, but they are rare.
Lastly, a true Hidden Mickey should not have to rely too much on imagination, such as the Matterhorn Mickey. If you must squint your eyes, tilt your head, and have a certain amount of lighting at a certain angle, it's probably not a Mickey. A Mickey may be upside down or sideways, but when pointed out, should be relatively clear, and not stretched out or partially obliterated like the Star Tours blast."
. We dont know if it is an official, unofficial, or just wishful thinking. Today we watched it on DVD and paused it. The hidden Mickey is 35 minutes into the film, right after the prisoners are freed from a cannon blast through the prison wall, Captain Jack Sparrow is still trapped. Then the British army fires a cannon in return, from that blast you see a large cloud of smoke in the shape of Mickeys head
. So can anyone confirm this or are we just pie eyed for Mickey? 
