Note: This is not relevant to the OP.
Quote:
Originally Posted by Kugelfang
Png format is considered 'lossless'. ... Png is generally better at compressing the file, though, so you can still achieve fairly small file sizes but without losing image quality. But png's more efficient compression does not quite match jpg's compression+lossiness in terms of created small file sizes.
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JPEG algorithms do best with uniform or smoothly blending colors (like painted textures or photographs, which have noise of their own): compression rates are very high, even at reasonable quality levels like 70, and the inevitable noise is less conspicuous. But when colors change abruptly, like with line art and text, PNG may compress better and never introduces noise (try it: draw hard edges on any raster editor, or just take a screen capture of your browser window right now, then save as JPG, and open the result. Zoom enough near text or sharp edges and you'll notice a swarm of pixels: they are inherent to the JPEG format, no matter your software).
Quote:
Originally Posted by Kugelfang
BTW, the reason Inkscape favors png is that jpg is a proprietary format (or at least was, the rights may have expired by now). Inkscape, being fairly serious about its open source roots, avoids incorporating proprietary technologies.
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Actually JPEG is standardized, and implemented by a free (as in freedom) library in Inkscape; however, it's probably patent-encumbered. IMHO a bigger factor is that each time a JPEG file is reopened and saved, quality degrades; changing a single pixel worsens the whole image.