As you're new to programming it's best to learn the sizes of datatypes now. When I first started out, I made the mistake of ignoring this but I've since caught up.
Every variable you create gets stored in RAM (memory). The datatype of the variable determines how much RAM is used. For example, integers and floats use 32 bits which equals 4 bytes. Strings are arrays of characters which are typically one byte each. For example "Hello World" uses 11 bytes, space included (it may actually be 12 bytes if there is a NULL character included by AppGameKit internally but we won't worry about this).
Arrays are like a table of variables and the amount of RAM an array takes up is Number_of_Elements * Array_Datatype_Size. An array of 10 integers will take up 40 bytes of RAM.
Let's do the maths with your current program. You have 500 variables (I'm assuming ints and floats) and 100 strings lets assume the average string character count (spaces included) is 1000. So we have 500*4 + 100 * 1000 = 102,000 bytes. Divide this by 1024 to get the number of kilobytes which equals approx. 100kb. The amount of RAM your variables are taking up (assuming 1000 chars per string) is 100kb. BatVink's array of floats alone is 40% larger. Compare 100kb to the size of your .png files. As baxslash stated, you're far more likely to run out of memory by loading in too much media than using too many variables.
