A nice shot of Janus.
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00163151.jpg

Some more (severe) data drop outs v_v.
http://saturn.jpl.nasa.gov/multimedia/imag...2/N00163150.jpg

Unlike MER, Cassini doesn't release raw images if their first transmission had data gaps; JPL holds back release of any Cassini images with data dropouts, in the hopes that Cassini will be able to retransmit the data. Once in a while, Cassini empties its data recorders (usually but not always in preparation for a targeted flyby) and then JPL has to give up on getting better versions of the images, with the result that you'll suddenly see a big batch of images with data dropouts and old dates hit the raw images website.

Cassini empties the recorders every few days, and almost never retransmits data. Retransmission is a planned, automatically-play-back-twice practice that's reserved for Titan and icy satellite encounters. You're probably seeing the difference between data the DSN sends to JPL immediately, and the "bested" data. There is some level of error correcting that the DSN can do, to recover packets corrupted in transmission, which they can't do on the fly. That is usually available a few days after the bits hit the ground. The really ratty data is probably from downlinks where the conditions were so bad that no amount of reprocessing and error correction can help.

I really like this image of Dione. It would make for a great desktop background. But I would just like to ask, is there be a version with less .jpg compression?

Those ring shadows are moving south pretty fast.

Those artifacts are in the raw jpegs, not caused by output compression setting so no.

I was afraid that might be the case, but I thought I'd ask. Thanks for the reply.

But wait six months and you'll have the 'real' raws with no compression!

Phil

For this particular observation that works out to 10 months.

for the image "dione_20100903.jpg"
"But I would just like to ask, is there be a version with less .jpg compression?"

they are not all that bad , i have seen far,far worse

in some of the celestia add on's ( some so bad i want to reject them )

but if you want here is a copy that i removed most from (as always, there is always a trade off with sharpness so...)

How many moons can you see in this image--four are easy and there may be 2-3 others?
Click to view attachment

I'm reckoning (without checking any simulators) that there are 6, and anticlockwise from bottom left they are:

Epimetheus, Daphnis, Pan, Janus, Enceladus and Atlas

Couldn't spy any more.....

Here's a rough guess on how that scene might have looked like:
Click to view attachment