PilotinControl, tell us how many photoresistors you want to read. Tell us which photoresistors they are (you can give a link to them). Tell us what you mean by "at once", how fast should they all be read (during a microsecond or during a minute) ? Tell us how many times per second you need the data. Tell us what your project is about.
If you have LDR resistors, they are slow anyway, and it would be okay to read them one by one during a millisecond.
If you would need a maximum of 12 analog inputs, then you can use a Arduino Leonardo.
If your project is to measure some kind of laser-doppler-interference pattern, then ... then I don't know.
If you ... and so on.