I have a whole folder devoted to these. Most of them have been models from older bryce files that the new system won't recognise for whatever reason. Save each model to a separate bryce image file named for the model, example: Castle Ruin. Place each in a folder for future use. When needed open the image, click on the mesh, control/Copy under edit, reopen the image you want the model in and do control/Paste. Somehow it doesn't make sense that you can open old image files but not have the ability to save the meshes. In some images I have actually come across situations where one mesh would save and another would not from the same image!