Why are images saved as JPEG ?

It lowers image quality a lot without much (if any) change in file size It does not make sense unless the image is BMP

sort by: active | newest | oldest
frollard7 years ago
Seconded! 

I know that bandwidth is a HUGE concern on a site like this; but png is WAY better than jpg in virtually every way.  at the same byte/pixel compression png has much higher quality than jpg.
I'm no pro, but maybe the system automatically reformats them to a specific size.
 
xACIDITYx8 years ago
I have no clue why 'Ibles does that; I think it may be to save space on the servers.
11010010110 (author)  xACIDITYx8 years ago
this is the answer but it does not allways have the wanted effect - and damages quality in most cases if the image is allready in jpeg - why open and save it again and not use as is ? it makes sense only when reducing image quality. maybe its not worth it after all. (even when saving in the same quality again image quality falls and size does not) if the image is in png (and probably gif too) converting it to jpeg makes it larger in size and makes quality loss jpeg is inexact in color and geometry. its good for photos where slight changes in color or blending are not important gif is exact in geometry and not in color. png is exact in both and is same quality as bmp. they are best for paint drawings (where geometry is most important) i now tried to draw something and save as png. then converted to jpeg. with jpeg quality set to minimum (1 % - image with spots of 10x10 pixel or more with wrong color) and it still takes more space than the png (which is exact color and geometry). png is suited for paint drawings (large areas of same color and limited amount of colors in the entire image) and jpeg is not if the image is bmp it should be converted to something else (bmp is huge in its nature). most bmps are paint drawings - so i'd convert them to png and not jpeg
Oh, well then I have no clue. I definitely prefer PNG's because they preserve "invisible" spots on them.