Rather than viewing two separate pictures side-by-side manually, save time by combining both pictures using Picasa’s Picture Collage Grid function. When combining, Picasa lets you modify the spacing between the pictures while also allowing you to use multiple pre-defined page formats to set the final size for the combined picture.
Click “File” on the Picasa main window, then use the “Add File to Picasa” option to add the pictures that you need to combine. After adding the pictures, hold down "Ctrl" and then click the thumbnails of both pictures on the Picasa window to select them.
Click “Create,” then click “Picture Collage” on the context menu. On the Collage tab that displays, use the pull-down menu under Settings to select “Grid.”
Use the slider under Grid Spacing to increase or decrease the space between both pictures. Drag the slider to the right to increase space, or drag it to the left to decrease space.
Use the pull-down menu under Page Format to select a format such as "16:10" (ideal for viewing on widescreen monitors), "4:3" (ideal for standard screen monitors) or "A4" (ideal for printing on A4 paper). Selecting a page format automatically adjusts the size of the combined picture, viewable on the preview pane to the right of the window.
Click “Create Collage” to combine both pictures.
Information in this article applies to Picasa 3.9. It may vary slightly or significantly with other versions.
To find combined pictures in Picasa, double-click "Projects" on the left navigation pane and then select "Collages." Right-click a combined picture and then select "Locate On Disk" to get to its storage location.