| Value | Meaning |
|---|---|
| greyscale0 | The data must be depth bits per pixel |
| truecolor2 | The data will be RGB triples, so depth * 3 bits per pixel. Depth must be 8 or 16. |
| indexed3 | The data must be depth bits per pixel, with a palette attached. Use writePng with IndexedImage for this mode. Depth must be <= 8. |
| greyscale_with_alpha4 | The data must be (grey, alpha) byte pairs for each pixel. Thus depth * 2 bits per pixel. Depth must be 8 or 16. |
| truecolor_with_alpha6 | The data must be RGBA quads for each pixel. Thus, depth * 4 bits per pixel. Depth must be 8 or 16. |
Represents the different types of png files, with numbers matching what the spec gives for filevalues.