It's because the images are too small and too low res. I don't know of any tool that would perfectly smooth the edges, so you're probably going to blow them up to several times the size, redo/smooth the outlines then save the large versions but save a duplicate with a high dpi then try shrinking them down again and see if they look better.
It's because the images are too small and too low res. I don't know of any tool that would perfectly smooth the edges, so you're probably going to blow them up to several times the size, redo/smooth the outlines then save the large versions but save a duplicate with a high dpi then try shrinking them down again and see if they look better.