I know they now shut down Picasa as in favor for the new Google Photos. I never used Picasa, but now uploaded a few pictures lately to Google Photos.But indeed when I visit https://picasaweb.google.com/home all the pictures from Google Photos show up there as well. Is that a normal behaviour?And more more point: Even though I only have very few albums created in Google Photos, in Picasa I see quite a lot of albums, named by dates. So for every date for which there are photos uploaded, one album is created in Picasa. Seems weird to me. 
Why pictures of Google Photos also show in Picasa Web frontend?
google photos;picasa web albums;upload
Yes, it's normal. Google Photos and Picasaweb (and presumably Google+ Photos) all simply use the same data store. I can't imagine that they would have wanted to copy all those petabytes of images from one place to another; better to just create a new app to point to the old data.