hmm, still looks a bit fuzzy. Did you save the jpg file as a png? If so then you'll want to redraw it, here comes the reasoning:
--->JPG
When you draw a picture in paint (or anyother program really) and save it as a jpg file details are made fuzzier. This probably has something to do with the way a jpg is compressed. Over time jpg files lose colors as they are altered and saved (try it some time, if you do it enough and compare it to the original you can notice it).
---->PNG
If you save it as a png file, although it is a bigger file, it saves everything without any loss in the compression. Additionally opening and saving the image repeatedly, unlike a jpg, will result in 0 loss.
JPG---->PNG
However, if you save it in a jpg first then as a png file it will still be fuzzy. This is because some of the data was already lost during the first conversion to jpg.
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Obviously straight to png is the best option. My recomendations are either redraw the image (long, tedious, and not fun) or cut the gun out (as closely to the lines as you can) using your favorite image editing software (paint, GIMP, photoshop, etc.) paste it into a new image and save it as a PNG. Good job on the art though.