Does Opengl Auto-Scale Texture Bit Depth ?

I was wondering about different bit depths, since my textures are all in 32 bit truecolor and I wanted to know how to go about scaling down to 16 bit. I saw this on another forum and would like to know if this is a true statement.

“You have to account for the bit depth of the users screen and convert your gfx when you load them. DX won’t, unfortunately, handle the conversions for you, but OpenGL will.”

glTexImage2D has 2 parameters (among others), ‘internalformat’ and ‘format’. ‘internalformat’ is what you want it to be on the graphic card. ‘format’ is what format the source image is in.

What bitdepth the user has on the desktop doesn’t matters to glTexImage2D.

Check reference for more details.