Alpha -> 16 or 32bit, 24 has no alpha. 16Bit has visible or invisible alpha only.
Reality: Cards that only capable of 16Bit (24 are out, 24bit mode is for desktop but totally worthless for games) will not run BM made games usefully. The last cards that were that slow that they needed that, don't have Hardware TnL ie they are not fully DX7 compliant.
They will suffer seriously from the full 3D approach of BlitzMax 2D support which will put an even larger strain on the CPU due to the missing TnL units. Those card most likely as well will have some pretty heavy constraints on the amount of VRAM that you can use.
What I first would need to check is how the Max2D handles image loading if you are on 16Bit only ie if you need to provide 16bit image data (would suggest to do that anyway so you see how the image will look at 16bit because automatic driver done conversion of the pixel formats can end in an ugly textures that only resembles the original very vaguely)
Reality: Cards that only capable of 16Bit (24 are out, 24bit mode is for desktop but totally worthless for games) will not run BM made games usefully. The last cards that were that slow that they needed that, don't have Hardware TnL ie they are not fully DX7 compliant.
They will suffer seriously from the full 3D approach of BlitzMax 2D support which will put an even larger strain on the CPU due to the missing TnL units. Those card most likely as well will have some pretty heavy constraints on the amount of VRAM that you can use.
What I first would need to check is how the Max2D handles image loading if you are on 16Bit only ie if you need to provide 16bit image data (would suggest to do that anyway so you see how the image will look at 16bit because automatic driver done conversion of the pixel formats can end in an ugly textures that only resembles the original very vaguely)