I'm no expert either. 
I'm not much experienced with arduino. But I can find my way around with codes.
Arduino - Wikipedia says arduino uno has 2kB RAM. We need an array of 2 colums(1 for red and other for blue). And max value is 255 for each variable, so we can use datatype byte. So we can have maximum (2*1024)/2=1024 columns. So we can very safely use an array of 100x2. That means you can have 100 different brightness levels for RGB LED and will need 100 RGB values. But you will also need to get 100 values for increasing brightness from the site. So you can set this to lesser value if you like.
Also, instead of creating so many if-else loops to check whther the photocell value is inbetween 0-99 or 100-199 or 200-299, you can divide the value by 100. then if the quotient comes out to be 0, its in 0-99, if its 1, its in 100-199 and so on. So the code could be something like:
byte RGB_values[100][2]={ {0,0},{2,5},{4,10},.........{108,250},{109,252},{110,255} };
int range;
//your codes...
 range=photocellReading/100;
 analogWrite(LEDAnalog[0], RGB_values[range][0]);
 analogWrite(LEDAnalog[1], 0);
 analogWrite(LEDAnalog[2], RGB_values[range][1]);
}
Do tell me if it works when you try it out.