Is it just to save disk space? Or does it affect loading time/performance in some way? You'd think that you'd want the best quality possible image for something you'll be looking at throughout the day.
Is it just to save disk space? Or does it affect loading time/performance in some way? You'd think that you'd want the best quality possible image for something you'll be looking at throughout the day.
There is the issue of space on the Live CD which is the primary distribution channel, but my understanding is that this is simply a legacy thing that has not yet been reviewed.
The difference between jpg and png when it comes to wallpaper is not all that important when you consider that wallpaper is not something that is carefully scrutinized as its often behind active windows.
If you feel strongly, and have comparable images to submit highlighting the advantages, create a bug report on Launchpad.
I see on launchpad that photos are compressed at 66%. I only looked for this after noticing the poor quality of the stock Ubuntu background images. The compression artefacts are really noticeable on larger screens.
This is obviously due to the space on the CD. So how about creating an ubuntu-wallpapers-hq package for high quality versions of the same images (not included on the CD but available for download). The package could automatically replace the existing package in order to avoid duplicates.
You are probably over-imagining both the loss due to good JPEG compression and your ability to detect that loss.
But since GNOME desktop is happy to use JPEGs or PNGs as a background, use whichever pleases you.