You can paste a PhotoRendered image of your project into this window, at File > Info > Project Preview.
Note: For best results, the image should be 320×240 pixels in size, a 4:3 ratio. If the image is another size, it will be cropped so as to achieve a 4:3 ratio and to fit the 320×240 pixel size.
Note: If you drag and drop, make sure you save the picture in JPEG format.
This preview is shown in the File > Open dialog box in order to make the identification of files easier. (This image will serve as the icon for the project file in Windows Explorer, replacing the standard ARCHICAD icon.)