Is there a general way to access an image asset from a script

I’m attempting to dynamically generate some terrain from a height map at run time. I imported the height map as an image asset but I can’t seem to find any documented way to access it that isn’t specific to textures or decals. Is there no API for simply retrieving image assets from a script?

I also couldn’t find any classes or functions to access the png as a bitmap so the bits could be used for generating terrain. I’m starting to think I’m barking up the wrong tree.