Picasa is limited to 1GB of storage (unless you pay up for more Google bytes) but now there's a free workaround. You can upload unlimited photos (smaller than 2048x2048) and videos (under 15 minutes) Google+ and it doesn't touch your storage limit. [ReadWriteWeb]
This was around before Google+ was out. Only thing that's changed with Google+ was that instead of what used to be 800x800 free size limit, it's now 2048x2048. Also,
Picasa automatically resizes your pictures to the acceptable free size once you take up your 1GB (which was also available before Google+).