// In the latest #googleplusupdate, you can now upload the full-sized photos and G+ will serve them accordingly: Initially you get a reduced (but great quality) version but you can zoon and pan to see more detail!

How to have this: To enable full-size desktop uploads, just visit your settings at https://www.google.com/settings/plus, and check "Upload my photos at full size." Afterwards, any files larger than 2048px will count towards your Google storage (up to 5GB free). Photo storage at 2048px or smaller remains free and unlimited.

Meanwhile, Facebook still can't keep up, probably not having enough servers/storage to handle better quality in their photos. See also this experiment by +Mike Elgan http://bit.ly/10y7JUH 

Finally, a reminder on how to zoom (try it on this 2448 x 3264 pixels photo from snowy Luxembourg :))
– use your mouse wheel to zoom in or out
– click and drag to pan right, left, up or down

Have fun!