Why are all my PNGs with IMAQdx saving as 24bit?

[gasalido]

I'm using a Basler Dart USB 3.0 camera with IMAQdx but despite having tried various "IMAQ Create" inputs including, "Grayscale (U8)", "Grayscale (I16)", "RGB (U32)", etc, my file is always 24bits, and my file size is always 6.76MB (uncompressed), which checks out for my resolution at 1920 x 1200 times the bit depth (24) divided by 8 bits to get to bytes = 6.912MB.

I thought I could save some file space for better performance when streaming by using a smaller bit depth, especially when the camera is only 10, 12 bits, but the 'image type' is always "RGB (U32)". How do I save at a lower bit depth? 

[RamonG]

Afaik when you grab the image the buffer is set to the bit depth of the camera, no matter what you initially set the buffer to using IMAQ create.

You can see this happening when you examine the type in Image Type 2 which is RGB U32, even though it was created as U8.

The solution would be to convert RGB to U8 after grabbing using IMAQ Cast Image.