Whilst Picasa is very intuitive and easy to pick up, it has a workspace that changes as you select different items, in other words its workspace is context sensitive. This makes it very simple to used but there is not one simple layout that applies to all action. In general terms picasa workspace is divided into 4 sections below the menu bar. The menu can access every action but I seldom use it.
The 4 section below the menu are a main screen, which will either display a number of photos in a given folder (as shown above) or a single photo as show below. In the library (or folder) view you can easily change the size of the thumbnail previews using the slider at the top line of the bottom tool bar.
There are then three separate tool bars, they change as you undertake different actions and activities.
The top tool bar has a few typical activities like import, creating a new album on the left and on the right there are filtering and a search option.
The left hand tool bar has two distinct modes. The first in the Library (or Navigation) View when you see several photos in the main window and it will assist you to scroll through your photos on your computer. The second view of this left hand tool bar is a series of tabbed tool for editing your photo and this appears when you have a single photo selected in the main window (see below) Just select and click a single photo in the library of folder view and you get transferred to the edit view. Click on the action key Back to Library and you get back to the main view.
The bottom tool bar performs some basic tasks like printing, emailing and sharing on google+ and there is a handy photo tray on the right hand side to show photos you have pinned (ie selected) and you can ten do group actions on them together.
There are a number of different edit functions, but I will discuss those separately in posts to come. Whilst google are clearly putting most effort into their on-line google+ photos area (which has taken over the on-line component to picasa). The PC version is still available for free download and if you want gain control of an unruly collection of photos it is really a good first stop.
I will finish off this workspace discussion with one of the most basic tools, yet very useful tools, for improving composition, the Crop. In Picasa you see the full image grey out but can view your crop selection as a full illuminated shape (rectangle of square). To aid the selection of standard sizes there is drop down menu, once a standard size is selected the aspect of the crop shape will be locked into that ratio and as you expand of contract one axis the other will automatically change. Here I am doing some preliminary compositional investigation for my Ingredients photo for the patch.
I will return later to the picasa workspace to discuss, metadata, albums and some of the more useful tools and filters.