An image by definition would always be represented as a 2D array. Unless you are using hologrophy or a projection field... which still in essence require a 2D array of representing the light field, often needing a higher resolution.
Images aren't always processed in 2D arrays though but are always represented in 2D arrays for display.
The problem is, of course, not in 2D arrays per se, but in the RAM and processing power wasted on processing arrays of pixels. You can still use 2D arrays, but in a more efficient fashion.
An image by definition would always be represented as a 2D array. Unless you are using hologrophy or a projection field... which still in essence require a 2D array of representing the light field, often needing a higher resolution.
Images aren't always processed in 2D arrays though but are always represented in 2D arrays for display.