There are three things a variable could be referring to
What type of variable is age?
Images are composed of pixels (this image is 1012 by 1520)
The color in each pixel is in RGB
Each band takes a value from 0-255
This image is data with 1020 x 1520 x 3 values.
To simplify, assume our photos are 8 x 8 grayscale images.
If you were to put the data from these (8 x 8 grayscale) images into a data frame, what would the dimensions of that data frame be in rows x columns?