can you convert a png to vector?

This is not "purist" propaganda. This is an attempt to help correct increasingly widespread gross marketing-driven misconception about what vector graphics is all about, in the context of auto-tracing routines.

There is no "conversion" between a raster image and a vector graphic. Strictly speaking, a true "conversion" would be a grid array of vector rectangles, which would have no practical advantage whatsoever over a raster image. Generating a vector version of a raster image is not a "conversion" in the sense of converting a TIF to a PNG. There is no "translation" of a raster image into a vector graphic in the sense of translating a Corel Draw file into an Illustrator file.

There is only redrawing what is represented by a raster image as paths, in the same sense that you can redraw an oil painting with a pencil. Autotrace routines (like Illustrator's so-called LiveTrace feature) try to automate that re-drawing by detecting regions of similarly-colored pixels. There is no shape-detection intelligence involved. The autotrace routine doesn't know that the eye's pupil is round or that a football is symmetrical (thus, the "distortion" you are taking about).

PNG is a raster image format. In a raster image, there is no shape to speak of, other than the rectangular bounds of the image.

The "image" you are talking about being distorted only exists in your human intelligence. You think of a region of similarly-colored pixels or related-color pixels as a particular shape. The auto-trace routine only sees the adjacent colors and tries to draw paths around them. LiveTrace knows nothing about what you perceive as a shape or an object, or an image.

You see a repeating pattern of intricate colors which you recognize as flowers, distorted by visual perspective on compound surfaces, overlaid by a pattern of shadows and highlights, and you recognize it as a couch. You see a few jagged edges that merely suggest a discrete shape and recognize it as the letter A.

An auto-trace routine sees only blotches of color with absolutely no meaningful correlation. You make settings to force it to "take a closer look" and it obligingly re-creates the inaccuracies of the blotches. It doesn't know that the distortion of the flowers and the shades of the lighting work together to describe the outline of a couch. It doesn't know that the top of the A is pointed and that its legs are diagonal.

There is huge benefit to be derived from re-drawing what is represented by a raster image as a set of accurate and economical vector paths--Those are the advantages people seek when they launch Illustrator and run LiveTrace, just because they've heard somewhere something like "vector is scaleable and raster isn't."

But in the vast majority of cases, there is no benefit whatsoever in "automatically" drawing those paths just on the basis of colors. Merely "being vector" doesn't necessarily yield the advantages of vector-based artwork; Being properly-drawn vector artwork does. Upscaling auto-traced results is usually just as ugly--or uglier--than merely upsampling the original raster image.

JET