Does JPG actually have any advantages over PNG?

Question

I recently overheard a conversation fragment, where one person was endlessly preaching the advantages of JPG over all other formats. In my experience, PNGs can do much more (transparency, better text display), while using up the same amount of space, if not less, than a JPG made from the same source PSD, AI, or raw captured image.

This got me thinking; does JPG actually have any advantages over PNG?

Answer 1

You are comparing apples to peaches, or what ever the correct idiom is.

PNG is lossless, jpg is by default lossy. PNG supports paletted images (e.g. 256 individual colors as GIF) and variable bit depth images, while JPG supports true color, 8 and 16 bits per channel images.

The source of these images differ. Other is used for vector or artificial graphics, other for photographs etc.

The purpose of the formats differ: one chooses PNG to store a bitmap font or company logo, but JPG to store desktop wallpaper image, to send holiday pictures to friends and to show (nonvector) graphics on a web page. The advantage is opportunity to trade quality to file size. Good quality photographs in JPEG take 2 bits per pixel, or 600kb for High Resolution (1920x1280). Same image compressed with PNG losslessy takes maybe 3-6 Mb. Some email providers would reject that large attachments to be sent or received.

Answer 2

PNGs can do much more (transparency, better text display), while using up the same amount of space

Besides the "better text display" remark (which makes little sense), the end of the statement is tipically false, specially when dealing with photographic images: in this sceneario (very common) JPEG uses much less space, it compresses much better, by using a lossy encoding. This is the main advantage of JPEG.

See for example here: http://en.wikipedia.org/wiki/Portable_Network_Graphics#Comparison_to_JPEG