Thank you for contacting National Instruments. IMAQ create returns a reference to the location in memory where the image will be stored, refer to the IMAQ Vision Concepts Manual page 1-6 (24) for more information about how image data is stored in memory. The memory is allocated for an image when you actually specify the size of the image to be stored at that memory location or acquire an image into the buffer. You can run out of memory quickly if you call imaq create inside a loop providing a different name for each buffer and allocating memory for each image. To clear out all memory allocated for images you can call IMAQ dispose and wire a true to the "All Images?" input. I hope this helps you out.
Regards, Nipun M Applications Engineer National Instruments