Is it possible to save an image as PNG-24 in IrfanView?
I am asking this because the edges around circular lines get disturbed when saving the image as transparent. I heard that this might be due to PNG-8 format.
Open the image, choose Image, Increase Color Depth and choose the 16million color option.
When you save as PNG it will be PNG-24 (ie, 24-bit color) format.
That may or may not solve the problem of raggedy edges.