I presume from the fact that you mention "fair use" that you're interested in United States law. In that case, the answer is a clear-cut "no".
17 USC 107:
Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include—
- the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
- the nature of the copyrighted work;
- the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
- the effect of the use upon the potential market for or value of the copyrighted work.
Let's look at your proposed use under these four factors:
The purpose of use: Commercial use, selling these movie clips for direct profit. You're not making any sort of transformative use (such as critical commentary), you're just re-using them as is. Big strike against you.
The nature of the copyrighted work: a work of fiction; your derivative is also an entertainment product. Another big strike.
The portion used: I haven't seen the clips in question, but you mention "famous scenes". That would work in your favor if you were using the clips for something like scholarship, but since you're not, the fact that these are the "important parts" works against you; the fact that they're small is irrelevant.
The effect on the potential market for the copyrighted work: This is a huge strike against you: your clips are directly displacing licensed use of the movie clips.
If I were a movie company and I caught you doing this, I'd bring out the big guns: I'd sue you for every penny you earned, plus substantial penalties, plus lawyer fees, plus everything else I could think of. And given the strength of the case against you, it's virtually certain you'd lose.
You might be tempted to compare what you're doing to animated-gif "image macros", but there's one major difference: the "macros" are generally used to compare a movie situation to an out-of-movie situation, making at least a gesture in the direction of transformative use and commentary. By pre-packinging your gifs, you're not commenting on anything.
Your only option for making what you're doing legal is to go to the copyright owners and ask for permission.