I never said that I was going to use a single battery?
It was just an idea.
I could run it with my own designed voltage booster.
That gives 3.9volts from a single 1.5volt battery.
That sounds to me like you're going to use one battery.
A Quick note: The Adafruit graphics test sketch compiles in just under 16Kb.
Half of the memory in a 328. Not efficient.
Adafruit libraries are many things, but rarely "small".
Code size can be a problem on Arduino. Reasons include:
a) The compiler is very aggressive about inlining (sensible use of "NOINLINE" can reduce code a *lot*)
b) Even though it's an 8-bit machine, all instructions are 16 bits
c) Pushing/popping of multiple registers needs one instruction per register, this can double the size of most functions.
d) Any kind of bit-manipulation code usually gets promoted to 16-bits, even when you're working with bytes.