Yeah, power can be adjusted through duty cycle. Spot size can be controlled, though less easily. The problem is the size if the test Lines I ran. They weren't long enough for the carriage to get up to speed, during which it increases power. Unfortunately, the compensation scheme it uses is fixed, but material response does not always match well. So, next time I do it, I'll dial down the speed to avoid the material response-compensation mismatch.
Virtually any image can be done, including photos. The software applies a dithering pattern to photos that depends on the material. Materials with a large heat affected zone require coarser dithering.