There are a lot more factors to look into other than what you want to do. For example, if you are more comfortable with certain programming languages or what you are willing to pay to develop. Generally, an iOS developer account will cost money (though you can download the sdk for free). If you are comfortable with C or any C variants, I recommend using iOS. If you are most comfortable with Java or OOP (Obect Oriented Programming), then use Android.
As for working with images, this is much simpler to do on iOS (many Android developers who work directly with bitmaps run out of memory quickly. iOS has some better built in methods here, and doesn't have the heap size limitation).
Lastly you should consider your audience. There is a better market for games on iOS, and more utility apps on Android. But obviously a good games is a good game, and people will buy it if you do a good job. As for cross-platforming, there are many tools or joint-languages that you can use, but for something so simple as this, I would recommend not wasting your time with those and go native for both OSes.