You can choose a focus point and export a 2D image from your original light field picture. The resulting 2D image will be a peak output of 4 Megapixels.
Peak output depends on a number of factors including how you've composed your shot, and the focal point that you select for output in your image.
You may also want to check out:
Can I print images from the LYTRO ILLUM? https://support.lytro.com/hc/en-us/articles/201679124
LYTRO ILLUM tech specs - https://support.lytro.com/hc/en-us/articles/201825730