This image, in addition to perhaps being a raster image which should be a vector, a Bad JPEG, an opaque image which should use transparency, or inappropriately low-resolution, is simply butt-ugly. Perhaps it was drawn with MSPaint by a two-year-old, or perhaps the author just wanted to inflict mental trauma on the rest of the Wikipedia community. In any case, the only solution is to redraw or recreate it from scratch, preferably looking at the original as little as possible to avoid brain damage.
I do SVG conversions as well as trying to keep the category for them tidy. In doing so, I come across a lot of butt-ugly images.