I know I can get the direct image URL from Picasa Web Album in a Public Album. And I can also get a lot of image URL in Google Product, such as Google Photos, Blogger, and Play Store. And this URLs all have some parameter to Change the Size of image.
For example, I get this two links in Picasa
The only difference is the size, which is controlled by the s144-Ic42 parameter. And If I manually changed the parameter, the size of image also changed.
And I get the direct link of the album cover from Google Play Store.
I found I can change the size through changing the w300-rw to s0 to get a larger one.
The question is how can I control the size of photo by changing some parameter? and another question is I can I get the same direct link in Google Photos after Picasa shut down?
After a little bit search, I found this site which answered my first question.
Best Answer
That site you found does answer your immediate question. But it doesn't address "can I get the same direct link in Google Photos after Picasa shut down?" - I think that the answer to that is still No.