r - How to know if any images were captured by the grDevices:png function? -

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i have following code capture images device 

png(filename="g:\\temp\\images1\\image%04d.png")

and dev.off() @ end of script

it works long have code in script creates/outputs image(s).

but if script not contain image plotting code , still blank image(the default 1 created when run png function) in specified folder .

is there way not add default image or delete if code not output image

for ex following script 

png(filename="g:\\temp\\images1\\image%04d.png")  x<- 2+ 3  dev.off()

after dev.off() , possible not have images in specified folder , or there way know if default image overwritten @ all


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