[OT] JPEG + graphs == hideous
Posted Jan 9, 2008 22:11 UTC (Wed) by roelofs
Parent article: What is RCU? Part 2: Usage
Please avoid using JPEG for anything but continuous-tone or photographic images. Of the common image formats, it is, by far, the worst possible choice for simple graphics like your diagrams and graphs. (Use PNG or GIF instead.) Leaving aside the visible flaws (e.g., note the splotchy green boxes with black text), you're also necessarily increasing the data size by an order of magnitude before compressing it, and I'm not aware of any compression algorithm that can make up the difference--certainly JPEG can't. In other words, not only is the quality worse, the files are bigger, too.
Btw, in case it wasn't obvious--and it's not to some people--don't convert your JPEGs to PNG or GIF to do the comparisons; the damage is already done. Save to a lossless format from the start. Virtually all Linux graphing and diagramming tools support PNG natively, and most now support GIF again, too. (Also make sure you save to "8-bit"/colormapped PNG, not 24-bit/RGB; zlib can't recover from the 3x-12x increase in size any more than JPEG can.)
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