Annotations relative to exported image border

i want to add some annotations (version string) to the lower left corner of the exported image (png). Currently i am using “paper” for the “xref” and “yref” attributes. These values need to adjusted for all the different plots i have. I was looking arround to see if there are any solutions which do not need to tweak position for this annotation for all the different plots. I just want to give it a position relative to the edges of the exporting image. Not at all related to the plot or data itself.