There's no need to take anyone else's code, emitting uncompressed DEFLATE blocks is trivial. I'm not sure what you mean by garbage? > for example 1024x1024x32b

There's no need to take anyone else's code, emitting uncompressed DEFLATE blocks is trivial. I'm not sure what you mean by garbage? > for example 1024x1024x32bit color means 3 megabytes for one image. You do miss something, that's 4 megabytes, plus any header/format overhead - but you'd get similar performance out of any uncompressed format, that's just the tradeoff.